Add option to control JPG quality when uploading an image (currently it auto-compresses JPGs)

From the customer:

I just noticed that when I upload a JPG image in an "Image upload" field in an extension, the image gets re-compressed (optimized). This is a great feature, but I would like to know is there a way to switch that off / circumvent it.

I would like to be able to fine-tune the compression/quality on a per-image basis (as you know, some images allow for a larger compression level without visible quality loss, while others suffer in some spots). Is that possible?

Using PNG is not always a good option - you know that PNGs can be 10+ times larger than a JPG with almost the same perceivable quality.