here is the basis for my assumption:
There are several foume posts stating that Staff_Jim is working on a site update. For something as large as kitmaker, and starting from fairly old code that may be incompatible with modern tools, this is not a trivial thing.
If I am not mistaken then the production site is currently used as development platform for new kitmaker software.
Normally this should not be done but it was given as an explanation some time ago to explain why the "fast reaction" field was not working anymore so it may be true.
If it is then irratic behaviour of the site is normal. You will have to wait until programming is finished.
A picture of 1200 x 900 pixels should be no more than about 200kb and an image of this size will upload and display well. this is the size we now use for features and reviews. I hope that helps.