diff --git a/js/imageProcessor.js b/js/imageProcessor.js
index 6e09245..d8f19d8 100644
--- a/js/imageProcessor.js
+++ b/js/imageProcessor.js
@@ -1,3 +1,17 @@
+/**
+ * Traite un tableau d'items avec au plus `concurrency` appels simultanés.
+ * @param {any[]} items
+ * @param {(item: any) => Promise<void>} processFn
+ * @param {number} concurrency
+ * @returns {Promise<void>}
+ */
 export async function processBatch(items, processFn, concurrency = 3) {
-  throw new Error('Not implemented');
+  const queue = [...items];
+  const workers = Array.from({ length: concurrency }, async () => {
+    while (queue.length > 0) {
+      const item = queue.shift();
+      if (item !== undefined) await processFn(item);
+    }
+  });
+  await Promise.all(workers);
 }
diff --git a/js/zipExporter.js b/js/zipExporter.js
index 5d59811..d377335 100644
--- a/js/zipExporter.js
+++ b/js/zipExporter.js
@@ -1,3 +1,22 @@
+/**
+ * Compresse les fichiers en ZIP et déclenche le téléchargement.
+ * @param {{ name: string, blob: Blob }[]} processedFiles
+ * @returns {Promise<void>}
+ */
 export async function downloadAllAsZip(processedFiles) {
-  throw new Error('Not implemented');
+  const zip = new JSZip();
+  for (const { name, blob } of processedFiles) {
+    zip.file(name, blob);
+  }
+  const zipBlob = await zip.generateAsync({ type: 'blob' });
+  const url = URL.createObjectURL(zipBlob);
+
+  const a = document.createElement('a');
+  a.href = url;
+  a.download = `photos-produits-${new Date().toISOString().slice(0, 10)}.zip`;
+  document.body.appendChild(a);
+  a.click();
+  document.body.removeChild(a);
+
+  setTimeout(() => URL.revokeObjectURL(url), 10_000);
 }