Title Image Problem

[SidelineSports]

When trying to add a new logo to my site, is a .gif format the only file format I can upload? Can I not use a .PNG formatted logo? I just had a logo company create a new logo for my site, and the final pack included a transparent .PNG logo, but I am having a problem putting it in as the Title Image.
Any help would be greatly appreciated.

[no mods]

You can make it a png.