fix: image download issue

Co-Authored-By: Clivia <132346501+Yanyutin753@users.noreply.github.com>

src/lib/components/common/ImagePreview.svelte

@@ -51,7 +51,7 @@
 				<button
 					class=" p-5"
 					on:click={() => {
-						downloadImage(src, 'Image.png');
+						downloadImage(src, src.substring(src.lastIndexOf('/') + 1));
 					}}
 				>
 					<svg