diff --git a/src/lib/format.ts b/src/lib/format.ts
new file mode 100644
index 0000000..7da9e37
--- /dev/null
+++ b/src/lib/format.ts
@@ -0,0 +1,67 @@
+// Zielformate & exakte Pixelberechnung (siehe 01 §5, 06 §3).
+// px = round(cm / 2.54 * dpi)
+
+export type Orientation = 'portrait' | 'landscape';
+
+export interface Dimensions { w: number; h: number; cm?: [number, number]; label: string; }
+
+// cm-Formate: [Breite, Höhe] in Hochformat-Konvention (kurze Seite × lange Seite)
+const CM: Record<string, [number, number]> = {
+  '9x13': [9, 13], '10x15': [10, 15], '13x18': [13, 18], '15x20': [15, 20],
+  '20x30': [20, 30], '30x40': [30, 40], '30x45': [30, 45], '40x50': [40, 50],
+  '40x60': [40, 60], '50x70': [50, 70], '60x90': [60, 90],
+  A4: [21, 29.7], A3: [29.7, 42], A2: [42, 59.4],
+  '20x20': [20, 20], '30x30': [30, 30],
+};
+
+// Reine Bildschirmformate (feste Pixel, kein cm/dpi)
+const SCREEN: Record<string, [number, number]> = {
+  theframe: [3840, 2160],   // 16:9 quer
+  hochformat: [2160, 3840], // 9:16 hoch
+};
+
+export const cmToPx = (cm: number, dpi: number) => Math.round((cm / 2.54) * dpi);
+
+export interface ResolveInput {
+  format: string;             // Schlüssel oben, 'sticker', 'custom' oder 'keep'
+  orientation?: Orientation;
+  dpi?: number;
+  customCm?: [number, number]; // für 'sticker'/'custom'
+}
+
+/** Liefert exakte Zielpixel + Label. `keep` → null (Original behalten). */
+export function resolveDimensions(input: ResolveInput): Dimensions | null {
+  const { format } = input;
+  const dpi = input.dpi ?? 300;
+  const orient = input.orientation ?? 'portrait';
+
+  if (format === 'keep') return null;
+
+  if (format in SCREEN) {
+    const [w, h] = SCREEN[format];
+    return { w, h, label: format === 'theframe' ? 'The Frame' : 'Hochformat' };
+  }
+
+  let cm: [number, number] | undefined;
+  if (format in CM) cm = CM[format];
+  else if (format === 'sticker' || format === 'custom') cm = input.customCm ?? [5, 5];
+  if (!cm) throw new Error(`Unbekanntes Format: ${format}`);
+
+  // Hochformat-Konvention → gewünschte Orientierung anwenden
+  let [wCm, hCm] = cm;
+  if (orient === 'landscape') [wCm, hCm] = [hCm, wCm];
+  return { w: cmToPx(wCm, dpi), h: cmToPx(hCm, dpi), cm: [wCm, hCm],
+           label: `${cm[0]}×${cm[1]} cm` };
+}
+
+/** Vereinfachtes Seitenverhältnis als "b:h" für die Bild-API. */
+export function aspectRatio(w: number, h: number): string {
+  const g = gcd(w, h);
+  return `${Math.round(w / g)}:${Math.round(h / g)}`;
+}
+function gcd(a: number, b: number): number { return b === 0 ? a : gcd(b, a % b); }
+
+/** Reicht die native Auflösung für echte 300 dpi? (Hinweis in der UI.) */
+export function upscaleWarning(srcW: number, srcH: number, target: Dimensions): boolean {
+  return srcW < target.w * 0.95 || srcH < target.h * 0.95;
+}
diff --git a/src/lib/init.ts b/src/lib/init.ts
index 57b6482..24579fb 100644
--- a/src/lib/init.ts
+++ b/src/lib/init.ts
@@ -1,6 +1,7 @@
 import { runMigrations } from './db';
 import { ensureBucket } from './storage';
 import { seed } from './seed';
+import { startImageWorker } from '../worker';
 
 let started: Promise<void> | null = null;
 
@@ -11,8 +12,8 @@ export function ensureInit(): Promise<void> {
       await runMigrations();
       try { await ensureBucket(); } catch (e) { console.error('[init] S3 nicht bereit:', e); }
       await seed();
+      try { await startImageWorker(); } catch (e) { console.error('[init] Worker-Start fehlgeschlagen:', e); }
       console.log('[init] Klarbild bereit.');
-      // TODO (Phase Bildkern): pg-boss-Worker hier starten.
     })().catch((e) => { started = null; throw e; });
   }
   return started;
diff --git a/src/lib/pipeline.ts b/src/lib/pipeline.ts
new file mode 100644
index 0000000..1bd6735
--- /dev/null
+++ b/src/lib/pipeline.ts
@@ -0,0 +1,94 @@
+import sharp from 'sharp';
+import type { Dimensions } from './format';
+
+export type CropMode = 'crop' | 'extend';
+
+/**
+ * Bringt ein (Modell-)Ergebnis exakt auf das Zielmaß und schreibt dpi-Metadaten.
+ * target=null → Original behalten (nur dpi setzen). Erhält Alpha, falls vorhanden.
+ */
+export async function finalizeToFormat(
+  buffer: Buffer,
+  target: Dimensions | null,
+  cropMode: CropMode,
+  dpi: number,
+): Promise<{ buffer: Buffer; width: number; height: number; hasAlpha: boolean }> {
+  let img = sharp(buffer, { failOn: 'none' });
+  const meta = await img.metadata();
+  const hasAlpha = !!meta.hasAlpha;
+
+  if (target) {
+    img = sharp(buffer, { failOn: 'none' }).resize(target.w, target.h, {
+      fit: 'cover',
+      position: cropMode === 'crop' ? sharp.strategy.attention : 'centre',
+    });
+  }
+
+  const out = await img
+    .withMetadata({ density: dpi })
+    .png({ compressionLevel: 9 })
+    .toBuffer({ resolveWithObject: true });
+
+  return { buffer: out.data, width: out.info.width, height: out.info.height, hasAlpha };
+}
+
+/**
+ * Weißer Stickerrand um das freigestellte Motiv (ohne Modell).
+ * Alpha extrahieren → Dilatation (Blur+Threshold) → weiße Konturebene → Original darüber.
+ * Radius = contourMm / 25.4 * dpi.
+ */
+export async function stickerContour(
+  buffer: Buffer,
+  contourMm: number,
+  dpi: number,
+): Promise<Buffer> {
+  const base = sharp(buffer, { failOn: 'none' }).ensureAlpha();
+  const { width, height } = await base.metadata();
+  if (!width || !height) throw new Error('Bildmaße unbekannt');
+
+  const radiusPx = Math.max(1, Math.round((contourMm / 25.4) * dpi));
+
+  // Alpha als Graustufenmaske, per Blur+Threshold verbreitern (Dilatation).
+  const mask = await sharp(buffer, { failOn: 'none' })
+    .ensureAlpha()
+    .extractChannel('alpha')
+    .blur(Math.max(0.3, radiusPx / 2))
+    .threshold(1)
+    .toColourspace('b-w')
+    .raw()
+    .toBuffer();
+
+  // Weiße Ebene, die verbreiterte Maske als Alpha.
+  const whiteLayer = await sharp({
+    create: { width, height, channels: 3, background: { r: 255, g: 255, b: 255 } },
+  })
+    .joinChannel(mask, { raw: { width, height, channels: 1 } })
+    .png()
+    .toBuffer();
+
+  // Original (RGBA) über die Konturebene legen.
+  const original = await base.png().toBuffer();
+  return sharp(whiteLayer)
+    .composite([{ input: original }])
+    .withMetadata({ density: dpi })
+    .png({ compressionLevel: 9 })
+    .toBuffer();
+}
+
+/** HEIC/HEIF → PNG-Puffer (sharp kann HEIC im Standard-Build meist nicht). */
+export async function heicToPng(buffer: Buffer): Promise<Buffer> {
+  const convert = (await import('heic-convert')).default as any;
+  const out = await convert({ buffer, format: 'PNG' });
+  return Buffer.from(out);
+}
+
+/** Deutscher Datei-Slug: klein, mit Bindestrichen, Format angehängt. */
+export function slugFilename(base: string, formatLabel: string, ext = 'png'): string {
+  const slug = (base || 'bild')
+    .toLowerCase()
+    .replace(/[äöüß]/g, (c) => ({ ä: 'ae', ö: 'oe', ü: 'ue', ß: 'ss' }[c] || c))
+    .normalize('NFKD').replace(/[̀-ͯ]/g, '')
+    .replace(/[^a-z0-9]+/g, '-').replace(/^-+|-+$/g, '').slice(0, 60) || 'bild';
+  const fmt = formatLabel.toLowerCase().replace(/[^a-z0-9]+/g, '');
+  return `${slug}${fmt ? '-' + fmt : ''}.${ext}`;
+}
diff --git a/src/lib/process.ts b/src/lib/process.ts
new file mode 100644
index 0000000..7d351c2
--- /dev/null
+++ b/src/lib/process.ts
@@ -0,0 +1,129 @@
+import { one, query } from './db';
+import { getObject, putObject, resultKey } from './storage';
+import { generateImage } from './openrouter';
+import { buildPrompt, type Task } from './prompts';
+import { resolveDimensions, aspectRatio, type Orientation } from './format';
+import { finalizeToFormat, stickerContour, slugFilename, type CropMode } from './pipeline';
+import sharp from 'sharp';
+
+const DEFAULT_MODEL = 'google/gemini-3.1-flash-image';
+
+interface RecipeSnapshot {
+  tasks: Task[];
+  output_format?: string;
+  orientation?: Orientation;
+  crop_mode?: CropMode;
+  dpi?: number;
+  contour_mm?: number | null;
+  model_key?: string | null;
+  custom_instruction?: string | null;
+  delivery?: 'library' | 'picdrop' | 'both';
+  picdrop_gallery?: string | null;
+}
+
+/** Welches Modell-ID + Alpha-Fähigkeit? Aus models-Tabelle, sonst Default. */
+async function pickModel(modelKey?: string | null): Promise<{ id: string; alpha: boolean }> {
+  if (modelKey) {
+    const m = await one<{ model_id: string; supports_alpha: boolean }>(
+      'SELECT model_id, supports_alpha FROM models WHERE label=$1 OR model_id=$1 LIMIT 1', [modelKey]);
+    if (m) return { id: m.model_id, alpha: m.supports_alpha };
+  }
+  const def = await one<{ model_id: string; supports_alpha: boolean }>(
+    'SELECT model_id, supports_alpha FROM models WHERE active AND is_default ORDER BY sort LIMIT 1');
+  if (def) return { id: def.model_id, alpha: def.supports_alpha };
+  return { id: DEFAULT_MODEL, alpha: true };
+}
+
+async function toDataUrl(buf: Buffer): Promise<string> {
+  const small = await sharp(buf, { failOn: 'none' })
+    .resize(1536, 1536, { fit: 'inside', withoutEnlargement: true })
+    .jpeg({ quality: 90 })
+    .toBuffer();
+  return `data:image/jpeg;base64,${small.toString('base64')}`;
+}
+
+export interface ProcessResult { ok: boolean; cost: number; error?: string; }
+
+/** Verarbeitet eine Position vollständig und aktualisiert ihren Datensatz. */
+export async function processItem(itemId: string): Promise<ProcessResult> {
+  const item = await one<{ id: string; job_id: string; source_path: string }>(
+    'SELECT id, job_id, source_path FROM items WHERE id=$1', [itemId]);
+  if (!item) return { ok: false, cost: 0, error: 'Position nicht gefunden' };
+
+  const job = await one<{ recipe_snapshot: RecipeSnapshot }>(
+    'SELECT recipe_snapshot FROM jobs WHERE id=$1', [item.job_id]);
+  const r = (job?.recipe_snapshot || {}) as RecipeSnapshot;
+  const tasks = r.tasks || [];
+  const dpi = r.dpi ?? 300;
+  const cropMode: CropMode = r.crop_mode === 'extend' ? 'extend' : 'crop';
+  const wantCutout = tasks.includes('cutout');
+  const wantContour = tasks.includes('contour');
+
+  await query(`UPDATE items SET status='running', attempts=attempts+1 WHERE id=$1`, [itemId]);
+
+  try {
+    const source = await getObject(item.source_path);
+    const target = r.tasks.includes('format') && r.output_format
+      ? resolveDimensions({ format: r.output_format, orientation: r.orientation, dpi })
+      : null;
+
+    const model = await pickModel(r.model_key);
+    const prompt = buildPrompt({ tasks, cropMode, customInstruction: r.custom_instruction });
+
+    // Nur Modell aufrufen, wenn eine generative Aufgabe dabei ist.
+    const needsModel = tasks.includes('clean') || wantCutout ||
+      (tasks.includes('format') && cropMode === 'extend') || !!r.custom_instruction;
+
+    let working = source;
+    let modelUsed: string | null = null;
+    let cost = 0;
+
+    if (needsModel) {
+      const gen = await generateImage({
+        model: model.id,
+        prompt,
+        inputUrl: await toDataUrl(source),
+        aspectRatio: target ? aspectRatio(target.w, target.h) : undefined,
+        background: wantCutout ? 'transparent' : undefined,
+        outputFormat: 'png',
+      });
+      working = gen.buffer;
+      modelUsed = gen.model;
+      cost = gen.cost;
+    }
+
+    // Lokale Nachbearbeitung: exakt aufs Zielmaß + dpi
+    const fin = await finalizeToFormat(working, target, cropMode, dpi);
+    let outBuf = fin.buffer;
+    let hasAlpha = fin.hasAlpha || wantCutout;
+
+    if (wantContour && r.contour_mm) {
+      outBuf = await stickerContour(outBuf, Number(r.contour_mm), dpi);
+      hasAlpha = true;
+    }
+
+    const key = resultKey(item.id);
+    await putObject(key, outBuf, 'image/png');
+
+    const label = target?.label || 'original';
+    const filename = slugFilename(label.replace(/\s+/g, '-'), target?.label || '');
+    const outputPx = `${fin.width}x${fin.height}`;
+    const deliveryStatus = (r.delivery === 'picdrop' || r.delivery === 'both') ? 'pending' : 'none';
+
+    await query(
+      `UPDATE items SET status='done', result_path=$2, filename=$3, output_px=$4, dpi=$5,
+        has_alpha=$6, model_used=$7, prompt_used=$8, cost=$9, error_message=NULL,
+        delivery_status=$10 WHERE id=$1`,
+      [itemId, key, filename, outputPx, dpi, hasAlpha, modelUsed, prompt.slice(0, 1000),
+       cost, deliveryStatus]);
+
+    return { ok: true, cost };
+  } catch (e: any) {
+    const msg = e?.friendly || e?.message || 'Unbekannter Fehler';
+    await query(`UPDATE items SET status='failed', error_message=$2 WHERE id=$1`,
+      [itemId, String(msg).slice(0, 500)]);
+    // 402/Guthaben: nach oben durchreichen, damit der Worker den Auftrag anhält
+    if (e?.status === 402) throw e;
+    return { ok: false, cost: 0, error: msg };
+  }
+}
diff --git a/src/lib/prompts.ts b/src/lib/prompts.ts
new file mode 100644
index 0000000..7db9814
--- /dev/null
+++ b/src/lib/prompts.ts
@@ -0,0 +1,45 @@
+// Aufgaben-Prompts für die Bild-API. Leitprinzip (01 §1): reproduzieren & erweitern,
+// nicht neu interpretieren. Farben, Komposition, Texturen und v.a. Lettering treu lassen.
+
+export type Task = 'clean' | 'cutout' | 'format' | 'contour' | 'deliver';
+
+const CLEAN =
+  'Recreate ONLY the actual artwork/motif as a clean, complete, high-resolution image. ' +
+  'Remove everything around it that is not part of the motif: picture frames, walls, ' +
+  'phone/app UI bars, shop overlays, cart icons, price tags, watermarks from your own ' +
+  'screenshot, timestamps and reflections. Reconstruct edges that were cropped or hidden. ' +
+  'Keep the original style, colors, textures, composition and ESPECIALLY any lettering ' +
+  'pixel-faithful. Do not reinterpret, do not add new elements.';
+
+const CUTOUT =
+  'Isolate only the main subject. The background must be fully transparent (alpha).';
+
+const FORMAT_EXTEND =
+  'Extend the scene naturally to fill the requested aspect ratio (outpainting), keeping ' +
+  'the existing composition centered and consistent in style.';
+
+const FORMAT_KEEP_RATIO =
+  'Produce the motif in the requested aspect ratio without distorting it.';
+
+export interface PromptOpts {
+  tasks: Task[];
+  cropMode?: 'crop' | 'extend';
+  customInstruction?: string | null;
+}
+
+/** Baut den kombinierten Prompt aus den Rezept-Aufgaben (feste Reihenfolge). */
+export function buildPrompt({ tasks, cropMode, customInstruction }: PromptOpts): string {
+  const parts: string[] = [];
+  if (tasks.includes('clean')) parts.push(CLEAN);
+  if (tasks.includes('cutout')) parts.push(CUTOUT);
+  if (tasks.includes('format')) {
+    parts.push(cropMode === 'extend' ? FORMAT_EXTEND : FORMAT_KEEP_RATIO);
+  }
+  if (!tasks.includes('clean') && !tasks.includes('cutout') && parts.length === 0) {
+    // reines Format ohne Bereinigen: nur reproduzieren
+    parts.push('Reproduce the image faithfully, no stylistic changes.');
+  }
+  if (customInstruction?.trim()) parts.push(`Additional instruction: ${customInstruction.trim()}`);
+  parts.push('Output only the resulting image.');
+  return parts.join(' ');
+}
diff --git a/src/lib/queue.ts b/src/lib/queue.ts
new file mode 100644
index 0000000..18ecc02
--- /dev/null
+++ b/src/lib/queue.ts
@@ -0,0 +1,34 @@
+import PgBoss from 'pg-boss';
+
+export const QUEUE = 'generate';
+export interface GenerateJob { itemId: string; jobId: string; }
+
+let boss: PgBoss | null = null;
+
+export async function getBoss(): Promise<PgBoss> {
+  if (!boss) {
+    boss = new PgBoss({ connectionString: process.env.DATABASE_URL });
+    boss.on('error', (e) => console.error('[pg-boss]', e));
+    await boss.start();
+    await boss.createQueue(QUEUE);
+  }
+  return boss;
+}
+
+export async function enqueue(job: GenerateJob): Promise<void> {
+  const b = await getBoss();
+  await b.send(QUEUE, job, { retryLimit: 2, retryBackoff: true });
+}
+
+export async function startWorker(
+  concurrency: number,
+  handler: (job: GenerateJob) => Promise<void>,
+): Promise<void> {
+  const b = await getBoss();
+  await b.work<GenerateJob>(
+    QUEUE,
+    { batchSize: Math.max(1, concurrency), pollingIntervalSeconds: 2 },
+    async (jobs) => { await Promise.all(jobs.map((j) => handler(j.data))); },
+  );
+  console.log(`[queue] Worker aktiv (Parallelität ${concurrency}).`);
+}
diff --git a/src/types/heic-convert.d.ts b/src/types/heic-convert.d.ts
new file mode 100644
index 0000000..c325f7a
--- /dev/null
+++ b/src/types/heic-convert.d.ts
@@ -0,0 +1,5 @@
+declare module 'heic-convert' {
+  interface ConvertOptions { buffer: Buffer; format: 'JPEG' | 'PNG'; quality?: number; }
+  const convert: (opts: ConvertOptions) => Promise<ArrayBuffer>;
+  export default convert;
+}
diff --git a/src/worker.ts b/src/worker.ts
new file mode 100644
index 0000000..5469e07
--- /dev/null
+++ b/src/worker.ts
@@ -0,0 +1,58 @@
+import { one, query } from './lib/db';
+import { startWorker, type GenerateJob } from './lib/queue';
+import { processItem } from './lib/process';
+
+/** Startet den Warteschlangen-Arbeiter (im selben Node-Prozess wie die App). */
+export async function startImageWorker(): Promise<void> {
+  const s = await one<{ concurrency: number }>('SELECT concurrency FROM settings WHERE id=1');
+  const concurrency = s?.concurrency ?? 2;
+  await startWorker(concurrency, handle);
+}
+
+async function handle(job: GenerateJob): Promise<void> {
+  // Angehaltene/abgebrochene Aufträge nicht verarbeiten.
+  const j = await one<{ status: string }>('SELECT status FROM jobs WHERE id=$1', [job.jobId]);
+  if (!j || j.status === 'paused' || j.status === 'cancelled') {
+    await query(`UPDATE items SET status='queued' WHERE id=$1 AND status='running'`, [job.itemId]);
+    return;
+  }
+  await query(`UPDATE jobs SET status='running' WHERE id=$1 AND status='queued'`, [job.jobId]);
+
+  try {
+    const res = await processItem(job.itemId);
+    if (res.ok) {
+      await query(`UPDATE jobs SET done_count=done_count+1 WHERE id=$1`, [job.jobId]);
+    } else {
+      await query(`UPDATE jobs SET failed_count=failed_count+1 WHERE id=$1`, [job.jobId]);
+    }
+  } catch (e: any) {
+    if (e?.status === 402) {
+      // Guthaben erschöpft → Auftrag anhalten, Position zurück in die Schlange.
+      await query(`UPDATE jobs SET status='paused' WHERE id=$1`, [job.jobId]);
+      await query(`UPDATE items SET status='queued', error_message='Guthaben erschöpft' WHERE id=$1`,
+        [job.itemId]);
+      console.error('[worker] 402 — Auftrag angehalten', job.jobId);
+      return;
+    }
+    await query(`UPDATE items SET status='failed', error_message=$2 WHERE id=$1`,
+      [job.itemId, String(e?.message || e).slice(0, 500)]);
+    await query(`UPDATE jobs SET failed_count=failed_count+1 WHERE id=$1`, [job.jobId]);
+  }
+
+  await maybeComplete(job.jobId);
+}
+
+/** Auftrag abschließen, wenn alle Positionen fertig/fehlgeschlagen sind. */
+async function maybeComplete(jobId: string): Promise<void> {
+  const row = await one<{ total: number; done: number; failed: number; open: number }>(
+    `SELECT total,
+       (SELECT count(*) FROM items WHERE job_id=$1 AND status='done')::int AS done,
+       (SELECT count(*) FROM items WHERE job_id=$1 AND status='failed')::int AS failed,
+       (SELECT count(*) FROM items WHERE job_id=$1 AND status IN ('queued','running'))::int AS open
+     FROM jobs WHERE id=$1`, [jobId]);
+  if (row && row.open === 0) {
+    await query(`UPDATE jobs SET status='done', finished_at=now() WHERE id=$1 AND status<>'cancelled'`,
+      [jobId]);
+    // TODO: Auslieferung (Picdrop) + Benachrichtigung (Telegram/n8n) anstoßen.
+  }
+}