Image uploading bug in Magento on Firefox
Today I discovered a problem with the way Magento allows you to upload images to attach to products: whenever I attempted to do so my entire browser would crash. (I'm using Firefox 2 on Linux.) Booting into Windows and using IE7 didn't suffer from this problem so it was clearly an issue with Firefox. Looking into it a bit further, Magento uses Flash/Flex to allow file uploads so this is likely the root cause of the issue.
Upgrading to the latest version of Flash – 126.96.36.199 at the time I wrote this – solves the problem and allows image uploads. So if you're having issues with getting this feature to work in Firefox I'd suggest upgrading Flash as the first thing to try.