feat: add click-to-preview for image attachments in chat

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/components/chat/message-input.tsx

@@ -29,6 +29,7 @@ import {
   DropdownMenuItem,
   DropdownMenuTrigger,
 } from "@/components/ui/dropdown-menu"
+import { ImagePreviewDialog } from "@/components/ui/image-preview-dialog"
 import { cn, randomUUID } from "@/lib/utils"
 import { matchShortcutEvent } from "@/lib/keyboard-shortcuts"
 import { useShortcutSettings } from "@/hooks/use-shortcut-settings"
@@ -303,6 +304,9 @@ export function MessageInput({
   })
   const [attachments, setAttachments] = useState<InputAttachment[]>([])
   const [isDragActive, setIsDragActive] = useState(false)
+  const [previewAttachmentId, setPreviewAttachmentId] = useState<string | null>(
+    null
+  )
   const containerRef = useRef<HTMLDivElement>(null)
   const textareaRef = useRef<HTMLTextAreaElement>(null)
   const lastDomDropAtRef = useRef(0)
@@ -394,6 +398,13 @@ export function MessageInput({
       ),
     [attachments]
   )
+  const previewAttachment = useMemo(
+    () =>
+      previewAttachmentId
+        ? (imageAttachments.find((a) => a.id === previewAttachmentId) ?? null)
+        : null,
+    [previewAttachmentId, imageAttachments]
+  )
   const resourceAttachments = useMemo(
     () =>
       attachments.filter(
@@ -1274,6 +1285,11 @@ export function MessageInput({
                   <div
                     key={attachment.id}
                     className="relative shrink-0 overflow-hidden rounded-md border border-border/70 bg-muted/30"
+                  >
+                    <button
+                      type="button"
+                      onClick={() => setPreviewAttachmentId(attachment.id)}
+                      className="cursor-pointer transition-opacity hover:opacity-80"
                     >
                       <Image
                         src={`data:${attachment.mimeType};base64,${attachment.data}`}
@@ -1283,6 +1299,7 @@ export function MessageInput({
                         unoptimized
                         className="h-14 w-14 object-cover"
                       />
+                    </button>
                     <button
                       type="button"
                       onClick={() => removeAttachment(attachment.id)}
@@ -1378,6 +1395,18 @@ export function MessageInput({
           {t("dropFilesToAttach")}
         </div>
       )}
+      <ImagePreviewDialog
+        src={
+          previewAttachment
+            ? `data:${previewAttachment.mimeType};base64,${previewAttachment.data}`
+            : ""
+        }
+        alt={previewAttachment?.name ?? ""}
+        open={previewAttachment !== null}
+        onOpenChange={(open) => {
+          if (!open) setPreviewAttachmentId(null)
+        }}
+      />
     </div>
   )
 }

src/components/message/user-image-attachments.tsx

@@ -1,7 +1,9 @@
 "use client"
 
+import { useState } from "react"
 import Image from "next/image"
 import type { UserImageDisplay } from "@/lib/adapters/ai-elements-adapter"
+import { ImagePreviewDialog } from "@/components/ui/image-preview-dialog"
 
 interface UserImageAttachmentsProps {
   images: UserImageDisplay[]
@@ -12,15 +14,24 @@ export function UserImageAttachments({
   images,
   className,
 }: UserImageAttachmentsProps) {
+  const [previewIndex, setPreviewIndex] = useState<number | null>(null)
+
   if (images.length === 0) return null
 
+  const previewImage =
+    previewIndex !== null && previewIndex < images.length
+      ? images[previewIndex]
+      : null
+
   return (
     <div className={className}>
       <div className="flex flex-wrap gap-1.5">
         {images.map((image, index) => (
-          <div
+          <button
             key={`${image.uri ?? image.name}-${index}`}
-            className="overflow-hidden rounded-md border border-border/70 bg-muted/30"
+            type="button"
+            onClick={() => setPreviewIndex(index)}
+            className="cursor-pointer overflow-hidden rounded-md border border-border/70 bg-muted/30 transition-opacity hover:opacity-80"
           >
             <Image
               src={`data:${image.mime_type};base64,${image.data}`}
@@ -30,9 +41,21 @@ export function UserImageAttachments({
               unoptimized
               className="h-14 w-14 object-cover"
             />
-          </div>
+          </button>
         ))}
       </div>
+      <ImagePreviewDialog
+        src={
+          previewImage
+            ? `data:${previewImage.mime_type};base64,${previewImage.data}`
+            : ""
+        }
+        alt={previewImage?.name ?? ""}
+        open={previewImage !== null}
+        onOpenChange={(open) => {
+          if (!open) setPreviewIndex(null)
+        }}
+      />
     </div>
   )
 }

src/components/ui/image-preview-dialog.tsx

@@ -0,0 +1,58 @@
+"use client"
+
+import { Dialog as DialogPrimitive } from "radix-ui"
+import { X } from "lucide-react"
+import { cn } from "@/lib/utils"
+
+interface ImagePreviewDialogProps {
+  src: string
+  alt: string
+  open: boolean
+  onOpenChange: (open: boolean) => void
+}
+
+function ImagePreviewDialog({
+  src,
+  alt,
+  open,
+  onOpenChange,
+}: ImagePreviewDialogProps) {
+  return (
+    <DialogPrimitive.Root open={open} onOpenChange={onOpenChange}>
+      <DialogPrimitive.Portal>
+        <DialogPrimitive.Overlay
+          className={cn(
+            "data-open:animate-in data-closed:animate-out data-closed:fade-out-0 data-open:fade-in-0",
+            "fixed inset-0 z-50 bg-black/80 duration-100 supports-backdrop-filter:backdrop-blur-xs"
+          )}
+        />
+        <DialogPrimitive.Content
+          className="fixed inset-0 z-50 flex items-center justify-center outline-none"
+          aria-describedby={undefined}
+          onClick={() => onOpenChange(false)}
+        >
+          <DialogPrimitive.Title className="sr-only">
+            {alt}
+          </DialogPrimitive.Title>
+          <button
+            type="button"
+            onClick={() => onOpenChange(false)}
+            className="absolute right-4 top-4 z-10 rounded-full bg-background/60 p-1.5 text-foreground/80 hover:bg-background/80 hover:text-foreground"
+            aria-label="Close"
+          >
+            <X className="h-5 w-5" />
+          </button>
+          {/* eslint-disable-next-line @next/next/no-img-element */}
+          <img
+            src={src}
+            alt={alt}
+            onClick={(e) => e.stopPropagation()}
+            className="max-h-[90vh] max-w-[90vw] rounded-lg object-contain"
+          />
+        </DialogPrimitive.Content>
+      </DialogPrimitive.Portal>
+    </DialogPrimitive.Root>
+  )
+}
+
+export { ImagePreviewDialog }