Hard to say if it's legal you would need to check with your local Insurance or Motor Vehicle office. Laws change from each province/state/country so you need to check for yours. I know where I live in Canada, BC. You can not have a custom license plate, they are all the same. You can pay extra to customize the words/numbers as long as it isn't taken; but there is never an image or print on the plate.
Even if you couldn't put it on a vehicle I could be cool to order a custom plate online with that image and maybe your username or something just as a decoration :)