(I haven't tested this, but it should work I think.)
If you don't want to use Javascript at all you may also be able to use the so-called sub-domain persistent connection trick.
Basically what you need to do is create separate sub-domains for each type of content, i.e. images.domain.com for static images and dynamic.domain.com for the kaleidoscope image script and keep
www.domain.com for serving up the HTML and CSS.
Doing this will trick most (if not all) browsers into loading the content in parallel instead of queuing up the requests in accordance to it's max-connections-per-domain setting that most browsers have built in. If it works it means the kaleidoscope image shouldn't block the requests to load the other images.