I totally understand this frustration. I think one of the issues we've started really running into in recent years is that there's now over 8.5k reference images in the figure study tool for full members, so when I add a hundred more it's really just a drop in the ocean - they're not that likely to shuffle up versus any other image. This is definitely a problem I'm working on in the rebuild I've been hard at work on, but I think we're still a couple months out from that being released.
In the meanwhile, there's a few things you could try --
If they are absolutely never appearing and you think there might actually be something wrong, you can try clearing out the photo cache in your tools here: https://line-of-action.com/user/cleartoolcaches
As a full member, you can create your own custom playlists from our library here: https://line-of-action.com/playlists which will enable you to select only the new images you're most intersted in for a session. :) When selecting images it does show the newest one first so they're easy to grab.