I was thinking about this and in case there isn't a fix anytime soon the workaround for this is to pull the image from the marketplace ( LINK ), change "med" in the link to "original", right click, save as, and then save it to your computer. Upload it back to the banner. Note: switching from Med to Original may not change the size, depends on how they have the image set up, but it is the best bet to get the best image quality.