I'm not sure if this will work on your computer, but I have a simple and easy way of doing it. I normally scan my pictures and upload them into paint. Then I go to image, scroll down to attributes and a box comes up. When the box comes up, there will be a box labeled height and a box labeled width. To upload fanart to this site, it says you have to have it 2000*2000 pixels so I normally type in 1999*1999. Sometimes the width or height is already below 2000 pixels, then you probably don't need to change it. When you're finshed resizing the picture, go to file, save and then you just sned it in to the sight! It's actually really simple!
