Fix issue where swiping a shared image without a directory made it disappear

svelte/src/filesystem/viewers/Image.svelte

@@ -52,14 +52,12 @@ export const update = async () => {
 	// Figure out if there are previous or next files. If not then we disable
 	// swiping controls in that direction
 	const siblings = await nav.get_siblings()
-	for (let i = 0; i < siblings.length; i++) {
-		if (siblings[i].name === nav.base.name) {
-			swipe_prev = i > 0
-			swipe_next = i < siblings.length-1
-			preload(siblings[i-1])
-			preload(siblings[i+1])
-			break
-		}
+	const i = siblings.findIndex(s => s.name === nav.base.name)
+	swipe_prev = i > 0
+	swipe_next = i !== -1 && i < siblings.length-1
+	if (i !== -1) {
+		preload(siblings[i-1])
+		preload(siblings[i+1])
 	}
 }