When deleting imagecategory id:1 action posted is id:0
Solution
in modules\system\admin\images\main.php line 554
replace
$imgcat_id = $system->cleanVars($_POST, 'imgcat_id', 0, 'int');
with
$imgcat_id = $system->cleanVars($_GET, 'imgcat_id', 0, 'int');
Could be more _POSTS needing to be replace.
In the alpha 2 is expected to make a new extension for images:
http://xoops.org/modules/news/article.php?storyid=6339