If you open a Imageshack account then as soon as you upload to that site your image is automatically resized, then you can copy and paste your image to the forum, or if you prefer use Photobucket you can, I have both these accounts but prefer Photobucket, better free editing software, but you do have to resize the photo's yourself, anyway in the Feedback and request section there's a good tutorial by Antad on how to upload photo's take a look.
Regards Jamie