What if you open them in a separate tab? That should work since startpage has nothing to do with that. EDIT: I just tested it. You can't get to the real picture for some reason and this is a bit annoying. But if you click on it and it opened in a new tab, right-click on it and select "Show in new tab" or "view image" - and you'll get a version where you have the whole image scaled correctly, and if too big you have the zoom cursor
Same problem in a new tab; e.g., a photo of Holly Willoughby: screenshot of the horribly upscaled preview opened in a new tab, vs. the real download, which is only 615x897 (maybe not the best example, as the real image is also a little blurry, lol)