User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:22.214.171.124) Gecko/20101203 Firefox/3.6.13 Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:126.96.36.199) Gecko/20101203 Firefox/3.6.13 The thumbnails on the tab-bar for the tabs have a lot of noise at times. This behavior is seen when the website is mobile optimized or moving from mobile optimized to a normal webpage in the same tab. Reproducible: Always Steps to Reproduce: 1. Go to m.google.com (mobile optimized) 2. Check the thumbnail (looks proper) 3. Navigate to a desktop version of the site using any of the links there 4. The thumbnail has a lot of noise (snapshot taken not properly saved probably) Actual Results: There is a lot of noise in the thumbnail. This seems to be like the PNG is not properly saved. Expected Results: There shouldn't be any noise.