Thought it might be helpful to follow up on my own issue here…
Yes, the location has apparently changed. I spent quite a bit of time tooling around and eventually downloaded a splashscreen.list file from the pi via winscp. When you open this file in notepad, it references the location of the splashscreen, which was here: “/home/pi/RetroPie-Setup/supplementary/splashscreens/retropieproject/splashscreen.png”
However, there was a larger issue, my file size (get it, wicked pun). When I built my png file, it ended up being huge, somewhere in the 2000×1000 range which also made the file size pretty jumbo too. This makes me wonder if uploading to the root works, but my file was too large, but I don’t think so.
Anyway, I uploaded to the location above, and it didn’t work, in fact it just dropped right into emustation. I grabbed the size from the default image, 590 x 393 which brought the size down to under 200k and uploaded again, wala, it works like a charm. So two points here…
File size: 590×393
Location: “/home/pi/RetroPie-Setup/supplementary/splashscreens/retropieproject/splashscreen.png”