diff --git a/components/Posting/Posting.php b/components/Posting/Posting.php
index e791792ef6..d84d84011a 100644
--- a/components/Posting/Posting.php
+++ b/components/Posting/Posting.php
@@ -29,6 +29,7 @@ use App\Core\GSFile;
 use function App\Core\I18n\_m;
 use App\Core\Modules\Component;
 use App\Core\Security;
+use App\Entity\Attachment;
 use App\Entity\AttachmentToNote;
 use App\Entity\Note;
 use App\Util\Common;
@@ -124,7 +125,7 @@ END;
         $matched_urls = [];
         preg_match_all(self::URL_REGEX, $content, $matched_urls, PREG_SET_ORDER);
         foreach ($matched_urls as $match) {
-            $processed_attachments[] = GSFile::validateAndStoreURL($url);
+            $processed_attachments[] = GSFile::validateAndStoreURL($match[0]);
         }
 
         DB::persist($note);
@@ -138,4 +139,15 @@ END;
             DB::flush();
         }
     }
+
+    /**
+     * Get a unique representation of a file on disk
+     *
+     * This can be used in the future to deduplicate images by visual content
+     */
+    public static function onHashFile(string $filename, ?string &$out_hash)
+    {
+        $out_hash = hash_file(Attachment::FILEHASH_ALGO, $filename);
+        return Event::stop;
+    }
 }
diff --git a/src/Core/GSFile.php b/src/Core/GSFile.php
index 60928a8908..e4164b5fc9 100644
--- a/src/Core/GSFile.php
+++ b/src/Core/GSFile.php
@@ -43,9 +43,9 @@ class GSFile
                                                       bool $is_local = true,
                                                       int $actor_id = null): Attachment
     {
+        Event::handle('HashFile', [$file->getPathname(), &$hash]);
         // The following properly gets the mimetype with `file` or other
         // available methods, so should be safe
-        $hash     = hash_file(Attachment::FILEHASH_ALGO, $sfile->getPathname());
         $mimetype = $sfile->getMimeType();
         Event::handle('AttachmentValidation', [&$sfile, &$mimetype]);
         $attachment = Attachment::create([
@@ -70,16 +70,17 @@ class GSFile
     public static function validateAndStoreURL(string $url): Attachment
     {
         if (Common::isValidHttpUrl($url)) {
-            HTTPClient::head($url);
+            $head       = HTTPClient::head($url);
             $headers    = $head->getHeaders();
             $headers    = array_change_key_case($headers, CASE_LOWER);
             $attachment = Attachment::create([
-                'remote_url'      => $match[0],
-                'remote_url_hash' => hash('sha256', $match[0]),
-                'mimetype'        => $headers['content-type'],
+                'remote_url'      => $url,
+                'remote_url_hash' => hash(Attachment::URLHASH_ALGO, $url),
+                'mimetype'        => $headers['content-type'][0],
+                'is_local'        => false,
             ]);
             DB::persist($attachment);
-            Event::handle('AttachmentStoreNew', [&$at]);
+            Event::handle('AttachmentStoreNew', [&$attachment]);
             return $attachment;
         } else {
             throw new \InvalidArgumentException();