diff --git a/frontend/src/repositories/Document.ts b/frontend/src/repositories/Document.ts
index b100449..7796bdd 100644
--- a/frontend/src/repositories/Document.ts
+++ b/frontend/src/repositories/Document.ts
@@ -37,21 +37,24 @@ export class Doc {
     return this.url.replace(/^\/#/, '')
   }
   get img(): boolean {
-    const ext = this.name.split('.').pop()?.toLowerCase() || ''
-    return ['jpg', 'jpeg', 'png', 'gif', 'webp', 'avif', 'heic', 'heif', 'svg'].includes(ext)
+    // Folders cannot be images
+    if (this.dir) return false
+    return ['jpg', 'jpeg', 'png', 'gif', 'webp', 'avif', 'heic', 'heif', 'svg'].includes(this.ext)
   }
   get previewable(): boolean {
+    // Folders cannot be previewable
+    if (this.dir) return false
     if (this.img) return true
-    const ext = this.name.split('.').pop()?.toLowerCase() || ''
     // Not a comprehensive list, but good enough for now
-    return ['mp4', 'mkv', 'webm', 'ogg', 'mp3', 'flac', 'aac', 'pdf'].includes(ext)
+    return ['mp4', 'mkv', 'webm', 'ogg', 'mp3', 'flac', 'aac', 'pdf'].includes(this.ext)
   }
   get previewurl(): string {
     return this.url.replace(/^\/files/, '/preview')
   }
   get ext(): string {
-    const ext = this.name.split('.').pop()
-    return ext ? ext.toLowerCase() : ''
+    const dotIndex = this.name.lastIndexOf('.')
+    if (dotIndex === -1 || dotIndex === this.name.length - 1) return ''
+    return this.name.slice(dotIndex + 1).toLowerCase()
   }
 }
 export type errorEvent = {
diff --git a/frontend/src/utils/index.ts b/frontend/src/utils/index.ts
index 870ffca..4df8b8f 100644
--- a/frontend/src/utils/index.ts
+++ b/frontend/src/utils/index.ts
@@ -50,12 +50,11 @@ export function formatUnixDate(t: number) {
 }
 
 export function getFileExtension(filename: string) {
-  const parts = filename.split('.')
-  if (parts.length > 1) {
-    return parts[parts.length - 1]
-  } else {
-    return '' // No hay extensión
+  const dotIndex = filename.lastIndexOf('.')
+  if (dotIndex === -1 || dotIndex === filename.length - 1) {
+    return '' // No extension
   }
+  return filename.slice(dotIndex + 1)
 }
 interface FileTypes {
   [key: string]: string[]
@@ -68,8 +67,9 @@ const filetypes: FileTypes = {
 }
 
 export function getFileType(name: string): string {
-  const ext = name.split('.').pop()?.toLowerCase()
-  if (!ext || ext.length === name.length) return 'unknown'
+  const dotIndex = name.lastIndexOf('.')
+  if (dotIndex === -1 || dotIndex === name.length - 1) return 'unknown'
+  const ext = name.slice(dotIndex + 1).toLowerCase()
   return Object.keys(filetypes).find(type => filetypes[type].includes(ext)) || 'unknown'
 }