Stopping image loading on homepage

[earthy]

I tested my homepage loading speed using http://tools.pingdom.com and found a few things that need to be tweaked or removed to make improvements.

One thing has stumped me though. The following is still attempting to load:

****.com/wp-content/uploads/2012/02/test-600x300.jpg

It was one of a series of different test images added to test pages to see how they viewed on the slider etc. Those pages are now deleted, I've checked existing pages and can't find any links to that original image, and I've deleted the image from the wp-content/uploads/2012/02 folder on my server. (and found loads of other old test images on there that should prob be deleted, right?).

Any idea how to stop this loading or where I should look aside from pages and posts to find where it might still be lurking? Perhaps there is a cache somewhere I should be purging..?

Stumped...