There's a visual puzzle consisting entirely of 1 image that I've originally made for a different community. Because it was locally successful, I thought it would be nice to share it with the world. However, the original image is a massive 460 MB 20000x20000 png, and it can be neither cropped (as it doesn't waste much space near the edges) nor significantly resized (as it contains small details that would become unreadable).
I have a compressed version of this file uploaded directly to imgur.com that's an under 20 MB 20000x20000 jpg, but my understanding is that questions on this site should be self-contained, and therefore I am not supposed to link to it. I determined that at around 10000x10000 I can get the file size down to 2 MB, which is the upload limit of i.stack.imgur.com, and still keep small details readable. Unfortunately, when I actually upload the image, it is always shrunk down to some size under 5000x5000, at which point it becomes too hard to discern a lot of the finer details.
It would definitely be possible to redesign the puzzle's aesthetics to make it more readable at lower image resolutions. That said, I've put a lot of time into making it look the way it does, and changing it now would require more work on my behalf than I ever intended to put into publishing it, so I wanted to ask if any alternatives exist. Is there some permissible way I can attach an under 2 MB 10000x10000 jpg image to a question unmodified?