RM doesn't warp images that it imports, so if the image isn't in Web Mecator (EPSG:3857) you might get the result that you see. You need to first warp the image from its current projection into the Web Mercator projection, before re-importing it into RM. If you want to send/share the image to This email address is being protected from spambots. You need JavaScript enabled to view it.
I can take a look.