So to recap, our current image settings are 3 MB maximum (you can upload much bigger than that, don’t worry), and it will then resize down on the forum server based on the max target size and the megapixels as well, as in, it will reduce the maximum image size to be no bigger than a 4K desktop size if it’s bigger than that (while keeping ratio).
When it gets a .bmp or a PNG then it will convert the original (and the thumbnails in the threads we see that are smaller) to a JPG at a quality rate of 95% (pretty hard to tell reduction in quality), meaning that a typical desktop screenshot should be less than 500 KB for the full original we store.
It’s really a compromise between storage costs, the power needed by the gerbils on the server to do the on-the-fly conversion at upload time and the bandwidth/caching ratio of people viewing on less than ideal connections. I could go back an ‘rebake’ all existing images, but the server would faint. The trouble is people live on all sides of the infernal globe, so it’s rare to get a quiet period to make the server all sweaty for hard batch image work.
Anyway, from now on it will be better.