Firefox crashes after image upload

Grrr - firefox crashes after I've uploaded a file to a website. Happens on geocaching.com, this blog and on Microsoft's site uploading a bug report. Very annoying as the whole browser crashes :-( Not sure what has caused this, probably some faulty extension or something. (It happens when the page you get after uploading a file is displayed). I've sent several reports back to Microsoft and the mozilla group, but the latter is annoying as most of the time the bug reporting application seems to freeze too :-(