Do you mean the thumbnail? Just take a screenshot of your game, paste it in some drawing program, crop a little square, and save it. Or copy some of your sprites and paste them in the same image.
I *think* I can help with your thumbnail problem. Not sure about the rest of submitting.
Basically, just screenshot any part of the game you want to show up as a thumbnail (the small pictures of games that appear in the homepage and such) and submit it to Photobucket. This website is able to crop and re-attribute the resolution of your wanted picture. All you have to do is edit your picture and type in 90 for both height and width. If it will not allow you to do that, then there should be a checkbox by an option that will allow you.
I believe AG only allows files from your computer, not by URL. So, after you get the size you want, right-click and copy the picture. Then paste it to Paint or something and save it. Now that you have the appropriate file for your thumbnail, you can submit it along with the rest of your work. I trust you have the rest figured out, ehehe....
Other than that, if your game is good as gold, you can expect it to be fully submitted within a week. Make sure it's your game, no mochi ads, yadda yadda, all that good stuff..........
