I love K2. My problem is the intricated schema used to put the pictures. There are no "picture" column in the "k2_items" table and the NAME of the picture is md5 crypted. It sucks! I lost an entire day to understand how it works.
The "heritage" scheme of categories is also confuse. after a couple of changes I lost the control and cannot retore the "default" status.
After all, the intricated CSS file make changes hard to do without a "error and atempt" hours expend.