Well, a 256 color (8 bit) .bmp file will work fine. It doesn't matter if your remote is color or not. You can "add frame" then double click on it, select icons and right click on the icon space and select load icon.
Now if this frame is the only thing on the page, you'll need to add a button with at least a delay on it for the page to be usable. Just move this blank button to the back so it doesn't show.
Jim L