5
xoops_imageurl is defined twice in XOOPS: xoopsroot / header.php and xoopsroot / include / common.php.
Change
'xoops_imageurl' => XOOPS_THEME_URL.'/'.$xoopsConfig['theme_set'].'/'
to
'xoops_imageurl' => 'http://www.yourdomain.com/pathtoimages/'
But as before mentionend, if you want to change the theme the path to the images will be wrong.