diff --git a/src/App.svelte b/src/App.svelte
index b12d3da..e5ef036 100644
--- a/src/App.svelte
+++ b/src/App.svelte
@@ -15,6 +15,7 @@
   import ChannelDialog from './ui/ChannelDialog.svelte';
   import PublicServers from './ui/PublicServers.svelte';
   import ServerInfoDialog from './ui/ServerInfoDialog.svelte';
+  import ImageViewer from './ui/ImageViewer.svelte';
   import ShareDialog from './ui/ShareDialog.svelte';
   import { share } from './lib/share.svelte.ts';
   import ResizeHandle from './ui/ResizeHandle.svelte';
@@ -63,13 +64,24 @@
     else ui.panelOpen = false;
   }
 
+  // Images in rendered text (messages, descriptions, the quick preview) and image embeds open
+  // large on click. Not in editors, link preview cards or the YouTube card.
+  function imageClick(e: MouseEvent) {
+    if (e.button !== 0 || !(e.target instanceof HTMLImageElement)) return;
+    const img = e.target;
+    if (!img.closest('.html, .embed') || img.closest('[contenteditable], .rich, .card, .yt')) return;
+    e.preventDefault();
+    e.stopPropagation();
+    ui.image = img.currentSrc || img.src;
+  }
+
   const closeOverlays = () => {
     navOpen = false;
     if (!panelInline) ui.panelOpen = false;
   };
 </script>
 
-<svelte:window bind:innerWidth={width} />
+<svelte:window bind:innerWidth={width} onclickcapture={imageClick} />
 
 {#snippet rail()}
   <ServerRail onadd={() => (editing = { server: null })} onedit={s => (editing = { server: s })} onbrowse={() => (ui.publicServers = true)}
@@ -134,6 +146,7 @@
 {/if}
 {#if share.dialog}<ShareDialog onclose={() => (share.dialog = null)} />{/if}
 {#if ui.prompt}<PromptDialog {...ui.prompt} onclose={() => { const p = ui.prompt; ui.prompt = null; p?.oncancel?.(); }} />{/if}
+<ImageViewer />
 <ContextMenu />
 
 <style>
diff --git a/src/app.css b/src/app.css
index c549161..95b0a0c 100644
--- a/src/app.css
+++ b/src/app.css
@@ -73,6 +73,10 @@ label { display: block; font-size: 12px; font-weight: 600; text-transform: upper
 .icon-btn:hover { background: var(--bg-hover); color: var(--text); }
 .icon-btn.on { color: var(--danger); }
 
+/* Images in rendered text open large on click (App.svelte) */
+.html img, .embed img { cursor: zoom-in; }
+.card img { cursor: inherit; }
+
 ::-webkit-scrollbar { width: 10px; height: 10px; }
 ::-webkit-scrollbar-thumb { background: var(--bg-3); border: 2px solid transparent; background-clip: padding-box; }
 ::-webkit-scrollbar-thumb:hover { background-color: var(--bg-active); }
diff --git a/src/lib/ui.svelte.ts b/src/lib/ui.svelte.ts
index 5a91d8b..ef80e79 100644
--- a/src/lib/ui.svelte.ts
+++ b/src/lib/ui.svelte.ts
@@ -30,6 +30,8 @@ class Ui {
   settingsTab = $state<'voice' | 'sounds' | 'appearance' | 'accessibility' | 'files' | 'identities'>('voice');
   publicServers = $state(false);
   serverInfo = $state(false);
+  // Image shown large (clicked in the chat or in a description)
+  image = $state<string | null>(null);
   // Set by the toolbar to open the own profile with the description editor
   editDescription = $state(false);
   // Add-server dialog, optionally prefilled (from the public list)
diff --git a/src/ui/ChannelNode.svelte b/src/ui/ChannelNode.svelte
index 4683405..e171521 100644
--- a/src/ui/ChannelNode.svelte
+++ b/src/ui/ChannelNode.svelte
@@ -49,8 +49,20 @@
   // Short grace period, so the pointer can move from the row into the preview
   function leaveRow() {
     clearTimeout(hoverTimer);
-    hoverTimer = setTimeout(() => (preview = null), 250);
+    // An image opened from the preview covers it; the preview stays underneath
+    hoverTimer = setTimeout(() => { if (!ui.image) preview = null; }, 250);
   }
+  // Back from the image: the preview stays while the pointer is on it, and goes when it is not
+  let popEl = $state<HTMLElement>();
+  let hadImage = false;
+  $effect(() => {
+    const open = !!ui.image;
+    if (hadImage && !open && preview && !popEl?.matches(':hover')) {
+      clearTimeout(hoverTimer);
+      hoverTimer = setTimeout(() => { if (!popEl?.matches(':hover')) preview = null; }, 1500);
+    }
+    hadImage = open;
+  });
   function showDescription() {
     clearTimeout(hoverTimer);
     preview = null;
@@ -131,7 +143,7 @@
     {/if}
   </div>
   {#if preview}
-    <div class="desc-pop" role="tooltip" style:left="{preview.x}px" style:top="{preview.y}px"
+    <div class="desc-pop" role="tooltip" bind:this={popEl} style:left="{preview.x}px" style:top="{preview.y}px"
       onmouseenter={() => clearTimeout(hoverTimer)} onmouseleave={leaveRow}>
       <strong>{channel.name || 'Root'}</strong>
       {#if descriptionHtml}<div class="html">{@html descriptionHtml}</div>{:else}<p>Loading description...</p>{/if}
diff --git a/src/ui/ImageViewer.svelte b/src/ui/ImageViewer.svelte
new file mode 100644
index 0000000..b156d66
--- /dev/null
+++ b/src/ui/ImageViewer.svelte
@@ -0,0 +1,25 @@
+<script lang="ts">
+  import { ui } from '../lib/ui.svelte.ts';
+
+  // An image from the chat or a description, as large as the window allows. A click anywhere
+  // or Escape closes it.
+  const src = $derived(ui.image);
+  const remote = $derived(!!src && /^https?:/i.test(src));
+</script>
+
+<svelte:window onkeydown={e => { if (src && e.key === 'Escape') { e.stopPropagation(); ui.image = null; } }} />
+
+{#if src}
+  <div class="viewer" role="dialog" aria-modal="true" aria-label="Image">
+    <button class="shade" aria-label="Close image" onclick={() => (ui.image = null)}></button>
+    <img {src} alt="" />
+    {#if remote}<a class="open" href={src} target="_blank" rel="noopener noreferrer">Open original</a>{/if}
+  </div>
+{/if}
+
+<style>
+  .viewer { position: fixed; inset: 0; z-index: 300; display: flex; align-items: center; justify-content: center; padding: 16px; }
+  .shade { position: absolute; inset: 0; background: rgb(0 0 0 / 0.85); cursor: zoom-out; }
+  img { position: relative; max-width: 100%; max-height: 100%; object-fit: contain; pointer-events: none; box-shadow: 0 16px 48px rgb(0 0 0 / 0.6); }
+  .open { position: absolute; bottom: 14px; left: 50%; transform: translateX(-50%); padding: 4px 10px; font-size: 13px; color: #fff; background: rgb(0 0 0 / 0.7); }
+</style>
diff --git a/test/e2e/app.e2e.ts b/test/e2e/app.e2e.ts
index 1eee29b..7413c5c 100644
--- a/test/e2e/app.e2e.ts
+++ b/test/e2e/app.e2e.ts
@@ -856,6 +856,19 @@ try {
   assert.ok(inline.length <= 131072, `inline image within the server limit (${inline.length})`);
   console.log(`ok: inline image without upload host (${inline.length} chars)`);
 
+  // A click on an image in the chat shows it large; Escape or a click closes it
+  await page.locator('.chat .msg .html img').last().click();
+  const viewer = page.getByRole('dialog', { name: 'Image' });
+  await viewer.waitFor();
+  const shown = await viewer.locator('img').evaluate((i: HTMLImageElement) => [i.naturalWidth > 0, i.getBoundingClientRect().width]);
+  assert.ok(shown[0] && (shown[1] as number) > 300, `image shown large: ${shown}`);
+  await page.keyboard.press('Escape');
+  await viewer.waitFor({ state: 'detached' });
+  await page.locator('.chat .msg .html img').last().click();
+  await viewer.getByRole('button', { name: 'Close image' }).click({ position: { x: 5, y: 5 } });
+  await viewer.waitFor({ state: 'detached' });
+  console.log('ok: images open large on click');
+
   // ─── Several servers at once ─────────────────────────────────────────────
   const userState = (name: string) => [...bob.users.values()].find(u => u.name === name);
   const until2 = (label: string, cond: () => boolean) => within(new Promise<void>(res => {