Olas is using a new kind for posting photos. I think right now most clients are using Kind 1. Olas is using Kind 20. I think Amethyst, at least off top of my head, is the only other client that lets you make a Kind 20 post.
Discussion
You know that center media tab in Amethyst that has had almost no use for a long time? Well, finally Olost stuff is showing up there and you can make a kind 20 post from that center media tab as well.