fuzzy thumbnails

[jasper98]

I recently switched hosts (to hostgator). Since then when I upload new images the thumbnails become very fuzzy. The images that I uploaded before switching still look pretty normal, although some look kinda bad as well (still no fuzzy though). See picture below:

 

 

You can see the top 3 thumbnails are blurry, however the full images look normal. (see popup) Anyone know what could be causing this and how to fix?

 

Here's another example in product description:

 

 

Looks the same in IE and Firefox.