because that is only 120,000 images at 1GB each
.... You really intend to take, develop, scan, and upload that many images?

I respect ambition.

jpg @ 85 or higher quality is pretty good.

png is, as you say, lossless, but it does compression

Since I had a 1GB TIFF (6x6 @ 6400 PPI / 48 bit) available, I decided to test the various formats:

TIF (1083 MB)
PNG (240 MB)
JPG (21.7 MB)