Uploading images fail, other documents upload just fine

I searched on Google but did not find a solution to this problem.

Maybe this is a nice challenge to you :) When I upload any document to my sharepoint site, it uploads just fine. I can upload using the website, SPD or WDAV.

However, when I try to upload a file with the extension .jpg .png and such the following happens. independent of the method I use to upload, after I hit the upload button it changes to the "processing" state and then after about 5 minutes it fails with a blank page.

Stating that it can't load the page. Within SPD it just keeps "processing" the file. Using WDAV it eventually does "copy" the file or so it looks. I think it creates an empty file with . format, because I can't open the actual image file, after it uploads using WDAV.

I'm running SP2010 on Win2k8sp2

Do you have any idea how to fix this, or where to start looking?