Mate I saw it straight away when someone posted that photo in the Facebook group. The figure in the doorway on the left, yeah? It's not just a shadow from the curtain like some people were saying, the shape is way too defined and you can make out what looks like shoulders.
Been to the Riverside Inn once a few years back and the place has a proper weird atmosphere even in daylight. Not surprised something showed up on camera honestly.
Anyone got the full set of photos from that night? Would love to see if anything else came up across the other rooms. These things tend not to appear in just the one shot in my experience, theres usually a pattern if you look through everything carefully.