I am using this great theme funkizine at my blog http://www.crackedbybinpda.com. The image at the header was repeating if the blog is opened in firefox or chrome and was quite annoying for me. Just checking the code for the bug causing header image to repeat even after the css having the no-repeat tag. I found an extra h1 code in the code. If you are using the same theme and are upset by the repeating image then remove the extra h1 tag and the extra image will disappear. Just 2 steps:
Update: I have shifted my blog to wordpress and using another cool theme.