Server to server is fine, but can take a long time to get the file locally (over my often crappy connection), and ideally I'd update several local sites using the marketplace rather than moving things around manually.
Yes, it seems to be only the admin user who sees this. The buttons work, but no icons appear. All other modules seem fine, so it is something I've coded wrongly but can't see what it could be.
I just tried changing the jrElastic screenshot images in the acp, enabled them, and reset the image cache. They show as active under the images tab, but the original screenshots still show under the info tab.