Fix regression in resizing JPEG images with Imagick (#5376)

Conflicts:

	program/lib/Roundcube/rcube_image.php

CHANGELOG

@@ -2,6 +2,7 @@ CHANGELOG Roundcube Webmail
 ===========================
 
 - Enigma: Add possibility to configure gpg-agent binary location (enigma_pgp_agent)
+- Fix regression in resizing JPEG images with Imagick (#5376)
 
 RELEASE 1.2.1
 -------------

program/lib/Roundcube/rcube_image.php

@@ -166,10 +166,16 @@ class rcube_image
                     else {
                         try {
                             $image = new Imagick($this->image_file);
-                            
-                            $image->setImageBackgroundColor('white');
-                            $image->setImageAlphaChannel(11);
-                            $image->mergeImageLayers(Imagick::LAYERMETHOD_FLATTEN);
+
+                            try {
+                                // it throws exception on formats not supporting these features
+                                $image->setImageBackgroundColor('white');
+                                $image->setImageAlphaChannel(11);
+                                $image->mergeImageLayers(Imagick::LAYERMETHOD_FLATTEN);
+                            }
+                            catch (Exception $e) {
+                                // ignore errors
+                            }
 
                             $image->setImageColorspace(Imagick::COLORSPACE_SRGB);
                             $image->setImageCompressionQuality(75);