Just some thoughts. If multiple users are sharing a cell tower, the more that are added the more congested the tower becomes, which then translates into weaker signal/range from LTE down to 3G to 1x. This is particularly evident on 3G and is the difference between a CDMA carrier and a GSM carrier. Sprint, of course, is CDMA. GSM will hold signal, but the quality of the signal reduces as the tower becomes more congested.
As to image compression…that's been a thing for a while now. Sprint is compressing images to reduce file size, which results in faster speeds. It's particularly evident with video streaming. Sprint will compress the heck out of that.