Right click on the picture you want to upload then. See Step 1
Click on Open With and select Paint.
Your photograph will probably be quite large.
Near the top of the page there is a tool bar See Step 2 go along and select Image. Then go down and select Resize/Skew. In the Resize boxes change the 100% to 50% this will reduce the size of your picture. You will probably have to do this a couple of times until you get the full picture on the screen. See Step 3
When you get your full picture on the screen. On the tool bar select Image them select Attributes See Step 4. Select Pixels if it is not selected. Enter 640 and 480 in the boxes.
If your photograph does not fit. On the tool bar select Edit then UNDO and try resizing a bit more.
When you have finished SAVE the paint file (I usually put it on desktop) Now go to the saved file and right click on it go down to Properties and check the data size.
On Mayhem, photos need to be 640 x 480 pixels (dimensions) & less than 160K Kilobytes
It is a bit long winded but once you do it a few times its quite quick