If you don't use WinXP, you can ignore this reply.
For anyone who uses XP and would like a quick and easy way to resize images, you can download and install the XP PowerToy Image Resizer. After install, find your file, right click and select 'Resize Pictures'. Either select a generic S/M/L size or click advanced for custom sizes.
I'd try selecting small and then trying to repost to the site.