Try to detect if an external attachment is an image or not.

Before we assumed that it is a picture in all cases.

src/Entity/Attachments/Attachment.php

@@ -144,9 +144,17 @@ abstract class Attachment extends AbstractNamedDBElement
      */
     public function isPicture(): bool
     {
-        //We can not check if an external link is a picture, so just assume this is false
         if ($this->isExternal()) {
-            return true;
+            //Check if we can extract a file extension from the URL
+            $extension = pathinfo(parse_url($this->path, PHP_URL_PATH) ?? '', PATHINFO_EXTENSION);
+
+            //If no extension is found or it is known picture extension, we assume that this is a picture extension
+            if ($extension === '' || in_array(strtolower($extension), static::PICTURE_EXTS, true)) {
+                return true;
+            }
+
+            //Otherwise we assume that the file is not a picture
+            return false;
         }
 
         $extension = pathinfo($this->getPath(), PATHINFO_EXTENSION);

tests/Entity/Attachments/AttachmentTest.php

@@ -182,8 +182,11 @@ class AttachmentTest extends TestCase
         return [
             ['%MEDIA%/foo/bar.txt', false],
             ['https://test.de/picture.jpeg', true],
+            ['https://test.de/picture.png?test=fdsj&width=34', true],
+            ['https://invalid.invalid/file.txt', false],
+            ['http://infsf.inda/file.zip?test', false],
             ['https://test.de', true],
-            ['http://test.de/google.de', true],
+            ['https://invalid.com/invalid/pic', true],
             ['%MEDIA%/foo/bar.jpeg', true],
             ['%MEDIA%/foo/bar.webp', true],
             ['%MEDIA%/foo', false],