Below are  a few examples of 254 X 92 (pixels) .PNG files with a transparent background.  Yours should be the EXACT same dimension/file type.

TIP: Notice how these are transparent PNG images… this will allow your logo to appear as if it is on the background.  If you do not want the background to display behind the logo, add a background color to the image.

Example 1:

Example 2:

Example 3:

Example 4: