Well the picture has probably been reversed at some point in its life. You'd be amazed how often that happens in the media. The short fat sling and 'ammo in cloak' detail looks like an attempt to copy from the Trajans column slingers. But look again at this picture.... how are you supposed to reload your sling if you are holding your cloak up like they are?

There looks like a sling plus arrow combo on the bottom right, although the arrow looks like it has a strap of its own attached so it might be a javelin and an unrelated hand-sling rather than an attempt to illustrate a kestros.

The staff sling on the bottom left has a manual release and no real freedom to swing for the pouch. I am not clear what is going on with the middle one.

I agree - the plate has almost certainly been reversed.

The illustration on the left, at least, appears to be 'after' Trajan's column, pictures in the images section of this site.

Oops, now I've properly read the earlier postings: I havn't written anything beyond David's stuff. Anyway I vote for most of the stuff he writes