Warning: imagejpeg() [function.imagejpeg]: SAFE MODE Restriction in effect. The script whose uid is 10053 is not allowed to access /var/www/vhosts/.../httpdocs/cache/jw_simpleImageGallery owned by uid 33 in /var/www/vhosts/.../httpdocs/plugins/content/jw_simpleImageGallery/jw_simpleImageGallery/includes/helper.php on line 134

Warning: imagejpeg() [function.imagejpeg]: Invalid filename in /var/www/vhosts/.../httpdocs/plugins/content/jw_simpleImageGallery/jw_simpleImageGallery/includes/helper.php on line 134

Solution :

You should give write access to folder cache/jw_simpleImageGallery