Roll-overs slow to load up

On my website (see below), I have quite a few roll-over vignettes. When loading up the home page first time with an empty cache, there is a rather lengthy load-up time on the right hand side of the display. Of course, once all the necessary information is stored in the cache, the load-up is almost instantaneous. How can I reduce the delay? I've already optimised the vignettes in Photoshop or at least I've optimised them to the best of my ability.
Took about 1 sec to load and maybe an additional 3secs to become functional for me. Works fine my end, can't ask for it be much faster than that.
Could be a number of things slowing it down. I'd say the main culprit is your web hosting. It's based in Utah and shared with over 3,000 other websites. As America wakes up it is bound to get slower and slower as the resources are stretched on the server. Plus requests are going to the US and back. I'd always recommend a good quality UK based hosting provider for a UK website. Pay a little more and you get a little more.

Whilst checking this I also noticed that the page is trying to access a SpryEffects.js file which is not available as the link path actually points to your computer! If it isn't needed then don't call it, if it is needed then repair the path and upload the file.

Few more things you could do to speed your site up, CSS in an external file would be a start, but sure you'll get your head around those as you learn.

Hope that helps.
Thanks for pointing out the broken link to the spryeffects file. I've fixed that now. Also, I looked at the link for google development which unfortunately I couldn't understand. I may just go back to Photoshop and attempt to optimise the display pictures again.