diff --git a/src/frontend/changelog.html b/src/frontend/changelog.html
index 0e0ece3..ac35d18 100644
--- a/src/frontend/changelog.html
+++ b/src/frontend/changelog.html
@@ -3,7 +3,7 @@
 <head>
 <meta charset="UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
-<title>Changelog — imagod-web v0.2.0+build.23-5a2e12d-dirty</title>
+<title>Changelog — imagod-web v0.2.0+build.24-0309359-dirty</title>
 <link rel="icon" href="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'><text y='.9em' font-size='90'>🖼️</text></svg>">
 <style>
 * { margin:0; padding:0; box-sizing:border-box; }
@@ -37,7 +37,7 @@ footer { text-align:center; color:#484f58; font-size:0.8rem; padding:2rem; }
 </head>
 <body>
 <header>
-  <h1>📋 imagod-web <span class="version-badge">v0.2.0+build.23-5a2e12d-dirty</span></h1>
+  <h1>📋 imagod-web <span class="version-badge">v0.2.0+build.24-0309359-dirty</span></h1>
   <nav>
     <a href="/">🖼️ Galerie</a>
     <a href="/changelog" class="active">📋 Changelog</a>
@@ -107,6 +107,6 @@ footer { text-align:center; color:#484f58; font-size:0.8rem; padding:2rem; }
 <h2>Légende des tags</h2>
 
 </main>
-<footer>imagod-web v0.2.0+build.23-5a2e12d-dirty — <a href="https://git.dracodev.net/Projets/imagod-web">Gitea</a></footer>
+<footer>imagod-web v0.2.0+build.24-0309359-dirty — <a href="https://git.dracodev.net/Projets/imagod-web">Gitea</a></footer>
 </body>
 </html>
diff --git a/src/frontend/help.html b/src/frontend/help.html
index f377d9b..93a5b67 100644
--- a/src/frontend/help.html
+++ b/src/frontend/help.html
@@ -3,7 +3,7 @@
 <head>
 <meta charset="UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
-<title>Aide & Roadmap — imagod-web v0.2.0+build.23-5a2e12d-dirty</title>
+<title>Aide & Roadmap — imagod-web v0.2.0+build.24-0309359-dirty</title>
 <link rel="icon" href="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'><text y='.9em' font-size='90'>🖼️</text></svg>">
 <style>
 * { margin:0; padding:0; box-sizing:border-box; }
@@ -37,7 +37,7 @@ footer { text-align:center; color:#484f58; font-size:0.8rem; padding:2rem; }
 </head>
 <body>
 <header>
-  <h1>❓ imagod-web <span class="version-badge">v0.2.0+build.23-5a2e12d-dirty</span></h1>
+  <h1>❓ imagod-web <span class="version-badge">v0.2.0+build.24-0309359-dirty</span></h1>
   <nav>
     <a href="/">🖼️ Galerie</a>
     <a href="/changelog">📋 Changelog</a>
@@ -169,6 +169,6 @@ footer { text-align:center; color:#484f58; font-size:0.8rem; padding:2rem; }
 <p>5. <strong>Corriger le backend Imago</strong> (thumbnails, upload, stockage)</p>
 
 </main>
-<footer>imagod-web v0.2.0+build.23-5a2e12d-dirty — <a href="https://git.dracodev.net/Projets/imagod-web">Gitea</a></footer>
+<footer>imagod-web v0.2.0+build.24-0309359-dirty — <a href="https://git.dracodev.net/Projets/imagod-web">Gitea</a></footer>
 </body>
 </html>
diff --git a/src/frontend/index.html b/src/frontend/index.html
index db63bf4..cc03d11 100644
--- a/src/frontend/index.html
+++ b/src/frontend/index.html
@@ -465,7 +465,7 @@
         <button class="btn" id="clear-btn" style="display:none">✕</button>
     </div>
     <button class="btn accent" id="header-upload-btn" onclick="document.getElementById('drop-zone').scrollIntoView({behavior:'smooth'}); document.getElementById('file-input').click()">📤 Upload</button>
-    <span class="version-badge" id="version-badge">v0.2.0+build.23-5a2e12d-dirty</span>
+    <span class="version-badge" id="version-badge">v0.2.0+build.24-0309359-dirty</span>
 </div>
 
 <!-- ─── Navigation ─── -->
@@ -911,8 +911,15 @@ function addTagInput(event, imgId) {
 }
 
 // ─── Upload ───
+let isUploading = false;  // Empêche les uploads parallèles
+
 async function uploadFiles(files) {
     if (!files || files.length === 0) return;
+    if (isUploading) {
+        showToast('Upload déjà en cours, veuillez patienter...', 'warning');
+        return;
+    }
+    isUploading = true;
 
     const zone = document.getElementById('drop-zone');
     let successCount = 0, errorCount = 0;
@@ -935,18 +942,35 @@ async function uploadFiles(files) {
             const data = await r.json();
 
             if (r.ok) {
-                successCount++;
-                showToast(`${file.name} uploadé !`, 'success', 3000);
+                // duplicate = l'image existe déjà → c'est un succès
+                if (data.status === 'duplicate') {
+                    successCount++;
+                    showToast(`${file.name} déjà existante (dédoublonnée) ✓`, 'info', 3000);
+                } else {
+                    successCount++;
+                    showToast(`${file.name} uploadée !`, 'success', 3000);
+                }
+            } else if (r.status === 409) {
+                // Conflit = upload concurrent → on attend un peu et on informe
+                showToast(`${file.name} : upload concurrent détecté, réessayez`, 'warning');
+                errorCount++;
             } else {
                 errorCount++;
                 showToast(`${file.name} : ${data.error || 'Échec'}`, 'error');
             }
         } catch(e) {
             errorCount++;
-            showToast(`${file.name} : ${e.message}`, 'error');
+            // Distinguer les types d'erreurs réseau
+            const msg = e.message || 'Erreur inconnue';
+            if (msg.includes('Failed to fetch') || msg.includes('NetworkError')) {
+                showToast(`${file.name} : serveur injoignable — vérifiez la connexion`, 'error');
+            } else {
+                showToast(`${file.name} : ${msg}`, 'error');
+            }
         }
     }
 
+    isUploading = false;
     zone.classList.remove('uploading');
     zone.querySelector('.drop-zone-text').textContent = 'Glissez-déposez des images ici';