I had planned to change this anyway for visually impaired Users as well as the same thing you mentioned previously where the correct image does not load in the Security Question. I tested it previously and I think it has something to do with Mobile Proxies.
The major problem for Mobiles is the Bottom Bar
. Mobiles have a problem with set images that do not scroll with a page. I thought about moving it before but I like it too much and it enables me to create other special effects. Eventually, mobiles will catch up. I have thought about creating a page that would allow Members to Post to here directly but still using the Mobile Skin to browse but this will take some major work because some Boards are Skin reliant, especially the role-playing games.