First, check your camera. Set the resolution to a lower setting.
Or; right click on the image you want to upload, click on edit, open the image tab, go to the skew and stretch, and reduce the file by %. Save it and then post it. Make sure your pictures are not "bit-map" format. Save them as "jpeg" file. There are also some photo editing programs that re-sizing is very easy. There are actually several good ways to re-size image's. I'm sure you'll hear about some others.
First I'd start with the camera picture size set-up.