Here is some additional info on a previous post on image and picture sizes and formats for the new Facebook pages:
Cover photos are 851 pixels wide and 315 pixels tall. If you upload an image that’s smaller than these dimensions, it will get stretched to this larger size. The image you upload must be at least 399 pixels wide.
Page profile pictures are square and, depending on the size of someone’s screen, display at 125×125 or 150×150 pixels. The photo you upload must be at least 180×180 pixels. We recommend uploading a square image of your brand’s logo. Rectangular images will be cropped to fit a square.
Page profile pictures display next to your Page’s name around the site, so yours should stand on its own to represent your Page. You can also be creative with how your profile picture and cover photo go together. On your Page’s cover, the profile picture displays 23 pixels from the left side and 239 pixels from the top of your cover photo.