Aside from all the technical concerns and such, there is one big factor here that argues against changing the picture posting process.
PRS is a guitar company. Their time, energy, and money is far better spent building guitars than maintaining a forum. You'd likely need at least one full-time person, maybe two (at minimum), which is two less positions available for the guitar business. And any additional cost is also going to take away from that.
I was not involved when this forum was set up, but my understanding is that several people really went to bat for us to convince the company to set this up when Birds And Moons went belly up. (And for the record, you couldn't paste pictures directly to BaM, either.)