Facebook application developer SkandNet released a list of guidelines for image sizes for the new timeline profiles for pages.

When you upload a picture that doesn’t match the space allotted on timeline, the site may adjust the image to fit, which can affect your resolution. Pictures that are too small get stretched, while oversized ones get squished.

The image sizes that SkandNet believes will be the most effective are — in pixels, width listed first:

  • Cover photo: 851 by 315;
  • Profile picture: 180 by 180;
  • App image: 111 by 74;
  • Thumbnail: 32 by 32;
  • Images within wall posts: 404 by 404; and
  • Highlighted and milestone images: 843 by 403.

The graphic below illustrates the location of each of these images.