In order to avoid image distortion it's important that your logo be (in pixels) a maximum of 715 wide x 100 tall.
The image can be in the .gif or .jpg file format. If your image uses less then 256 colors we recommend GIF. If it's more then 256 colors we recommend JPG.

Ideally the smaller the file size of the header graphic, the better as performance is increased when header images are optimized.

See below for example image size:

Once you have located an image you'd like, submit a request in the upper right-hand corner of this page, including the image you wish to use.