diff --git a/app/RSpade/Core/Files/File_Attachment_Controller.php b/app/RSpade/Core/Files/File_Attachment_Controller.php
index ebe445cc3..a2a7fbe63 100644
--- a/app/RSpade/Core/Files/File_Attachment_Controller.php
+++ b/app/RSpade/Core/Files/File_Attachment_Controller.php
@@ -56,7 +56,7 @@ use App\RSpade\Core\Session\Session;
  *
  * GET /_download/:key                               - Download file as attachment
  * GET /_inline/:key                                 - View file inline (browser display)
- * GET /_thumbnail/:key/:type/:width/:height?        - Generate static thumbnail (WebP)
+ * GET /_thumbnail/dynamic/:key/:type/:width/:height? - Generate dynamic thumbnail (WebP)
  * GET /_icon_by_extension/:extension                - Get file type icon as PNG
  *
  * FILE RESPONSE PATTERN:
@@ -561,7 +561,7 @@ class File_Attachment_Controller extends Rsx_Controller_Abstract
     /**
      * Generate dynamic thumbnail for image attachments
      *
-     * Route: /_thumbnail/:key/:type/:width/:height?
+     * Route: /_thumbnail/dynamic/:key/:type/:width/:height?
      *
      * Security: Checks file.thumbnail.authorize only
      *
@@ -570,7 +570,7 @@ class File_Attachment_Controller extends Rsx_Controller_Abstract
      * @param int    $width  Thumbnail width in pixels
      * @param int    $height Optional thumbnail height in pixels
      */
-    #[Route('/_thumbnail/:key/:type/:width/:height?', methods: ['GET'])]
+    #[Route('/_thumbnail/dynamic/:key/:type/:width/:height?', methods: ['GET'])]
     #[Auth('Permission::anybody()')]
     public static function thumbnail(Request $request, array $params = [])
     {
diff --git a/app/RSpade/Core/Files/File_Attachment_Model.php b/app/RSpade/Core/Files/File_Attachment_Model.php
index 69380bf4d..cf9badb12 100644
--- a/app/RSpade/Core/Files/File_Attachment_Model.php
+++ b/app/RSpade/Core/Files/File_Attachment_Model.php
@@ -264,9 +264,9 @@ class File_Attachment_Model extends Rsx_Site_Model_Abstract
     public function get_thumbnail_url($type = 'fit', $width = 400, $height = null)
     {
         if ($height === null) {
-            return url("/_thumbnail/{$this->key}/{$type}/{$width}");
+            return url("/_thumbnail/dynamic/{$this->key}/{$type}/{$width}");
         }
-        return url("/_thumbnail/{$this->key}/{$type}/{$width}/{$height}");
+        return url("/_thumbnail/dynamic/{$this->key}/{$type}/{$width}/{$height}");
     }
 
     /**
diff --git a/app/RSpade/Core/Files/THUMBNAILS.md b/app/RSpade/Core/Files/THUMBNAILS.md
index 2eb8a8047..12a359c17 100755
--- a/app/RSpade/Core/Files/THUMBNAILS.md
+++ b/app/RSpade/Core/Files/THUMBNAILS.md
@@ -53,7 +53,7 @@ Edge case: Identical file content uploaded with different extensions (e.g., `doc
 
 ### Request Processing
 
-**Route**: `/_thumbnail/:key/:type/:width/:height` (dynamic) or `/_thumbnail/preset/:key/:preset_name` (preset)
+**Route**: `/_thumbnail/dynamic/:key/:type/:width/:height` (dynamic) or `/_thumbnail/preset/:key/:preset_name` (preset)
 
 **Common Flow** (via `generate_and_serve_thumbnail()`):
 1. Validate authorization (`file.thumbnail.authorize` event)
diff --git a/app/RSpade/man/file_upload.txt b/app/RSpade/man/file_upload.txt
index d04ecc123..fe2ed3ba3 100755
--- a/app/RSpade/man/file_upload.txt
+++ b/app/RSpade/man/file_upload.txt
@@ -397,7 +397,7 @@ HTTP ENDPOINTS
         POST   /_upload                                   - Upload file
         GET    /_download/:key                            - Download file
         GET    /_inline/:key                              - View file inline
-        GET    /_thumbnail/:key/:type/:width/:height?     - Generate thumbnail
+        GET    /_thumbnail/dynamic/:key/:type/:width/:height? - Generate dynamic thumbnail
         GET    /_icon_by_extension/:extension             - Get file type icon
 
 UPLOAD ENDPOINT
@@ -594,9 +594,9 @@ DOWNLOAD AND INLINE VIEWING
 
 THUMBNAIL GENERATION
 
-    GET /_thumbnail/:key/:type/:width/:height?
+    GET /_thumbnail/dynamic/:key/:type/:width/:height?
 
-    Generate thumbnails for uploaded files with automatic fallback to file type icons.
+    Generate dynamic thumbnails for uploaded files with automatic fallback to file type icons.
 
     URL Parameters:
         key     - 64-character attachment key
diff --git a/app/RSpade/upstream_changes/thumbnail_url_routes_01_28.txt b/app/RSpade/upstream_changes/thumbnail_url_routes_01_28.txt
new file mode 100755
index 000000000..fdbb24c66
--- /dev/null
+++ b/app/RSpade/upstream_changes/thumbnail_url_routes_01_28.txt
@@ -0,0 +1,69 @@
+Thumbnail URL Route Changes
+Date: 2026-01-28
+
+SUMMARY
+    Both thumbnail routes now include a literal path segment to prevent route
+    matching conflicts. If you manually construct thumbnail URLs (rather than
+    using get_thumbnail_url() or get_thumbnail_url_preset()), update them.
+
+    - Preset: /_thumbnail/preset/{key}/{preset_name}  (unchanged from earlier today)
+    - Dynamic: /_thumbnail/dynamic/{key}/{type}/{width}/{height}  (NEW)
+
+AFFECTED FILES
+    /rsx/app/dev/attachments/dev_attachments.js
+    /rsx/theme/components/inputs/photo/profile_photo_input.js
+
+    Any custom code manually constructing thumbnail URLs.
+
+CHANGES REQUIRED
+
+    If you manually construct dynamic thumbnail URLs, add "dynamic" segment:
+
+    Before:
+        `/_thumbnail/${key}/cover/300/200`
+        `/_thumbnail/${key}/fit/400`
+
+    After:
+        `/_thumbnail/dynamic/${key}/cover/300/200`
+        `/_thumbnail/dynamic/${key}/fit/400`
+
+    File: /rsx/app/dev/attachments/dev_attachments.js
+    -------------------------------------------------------------------------
+    Find:
+        $('#thumb-profile').attr('src', `/_thumbnail/${key}/cover/96/96`);
+        $('#thumb-200').attr('src', `/_thumbnail/${key}/cover/200/200`);
+        $('#thumb-240x180').attr('src', `/_thumbnail/${key}/cover/240/180`);
+
+    Replace with:
+        $('#thumb-profile').attr('src', `/_thumbnail/dynamic/${key}/cover/96/96`);
+        $('#thumb-200').attr('src', `/_thumbnail/dynamic/${key}/cover/200/200`);
+        $('#thumb-240x180').attr('src', `/_thumbnail/dynamic/${key}/cover/240/180`);
+
+    File: /rsx/theme/components/inputs/photo/profile_photo_input.js
+    -------------------------------------------------------------------------
+    Find:
+        this.state.thumbnail_url = `/_thumbnail/${this.state.attachment_key}/cover/${width}/${height}`;
+
+    Replace with:
+        this.state.thumbnail_url = `/_thumbnail/dynamic/${this.state.attachment_key}/cover/${width}/${height}`;
+
+RECOMMENDED APPROACH
+
+    Instead of manually constructing URLs, use the model methods which always
+    generate correct URLs:
+
+    PHP:
+        $attachment->get_thumbnail_url('cover', 300, 200);
+        $attachment->get_thumbnail_url_preset('profile');
+
+    JavaScript (via Ajax stub):
+        const url = await File_Attachment_Model.get_thumbnail_url(key, 'cover', 300, 200);
+
+VERIFICATION
+
+    1. Search your codebase for manual thumbnail URL construction:
+       grep -r "/_thumbnail/" rsx/ --include="*.js" --include="*.php"
+
+    2. Update any matches that don't use get_thumbnail_url methods
+
+    3. Test thumbnail display in your application