I'm building a website at the moment that has several complicated background images and repeats. The file sizes for each of the images are quite large (I've compressed them down as much as possible!), is there an online tool that I can use to measure the filesize of a page?
I found this from searching for a couple of minutes, looks like it may do the trick for you!
I don't know of any online tools personally, though if it were me I would just select your image folder(s) and html, js, stylesheet files and look at the collective filesize that way.
There is always the page speed addon for Firefox/Chrome that will give you recommendations for other optimizations you can do to improve the speed of your site.
Hope this helps.
The Web Developer Toolbar for Firefox has a "View Document Size" item under the Information menu. (This option is missing in the Chrome version, for some reason.) It opens a tab that shows you overall size, broken down by section(images, scripts, stylesheets, etc) which you can toggle open for a detailed listing, in case you need to hunt down a particular item that's a problem.