How do I make an iGoogle theme?

Every time I want to upload a picture it tells me my pictures need to be at least 680 px by whatever. How big is that exactly? I think I can figure it out from there I just want a picture up!!!!!!|||The picture you are using for your theme is obviously not big enough. You can search Google Images and select how big the image you want to search is. Once you find a picture, save it to your computer and upload the picture to iGoogle, if it is still not big enough the find a bigger image. I hope I helped.