Before you upload images to the site you may want/need to resize them. For example the forum requires you to post images no bigger that 499x499.

If you are using Windows XP there is a very easy way to do this.  You need a piece of software that is free from Microsoft. It's part of the Windows XP Powertoys. You can download it from here. 

Once the software is installed you simply right click on your image and choose Resize Pictures. A pop up will appear. Choose the size you want, the smallest two are adequate for most websites. That's pretty much it, there will be a new file (your original image is left unchanged) in the same folder as the original.