Saving banners

Ok, this is really driving me nuts. I've tried the thing in the memories but I just can't get it to work. I made a banner tonight, and I uploaded it onto photobucket. The problem is, I can't get it to show up on LJ. And when I click the thumbnail in photobucket, it doesn't shot up big like the other icons I have on there! It's saved as a jpg and it's 51.5kb. Does it have to be under 40k to show up? Because I saved another that's 21.1 kb and that's not showing up either. I have the script right, I've checked it a million times and I'm about to tear my hair out. Thanks for the help guys.