EDIT: I forgot to add a screenshot. Here it is.
While re-watching DS9 S1:E19 "Duet", I noticed this okudagram around 6:21 and got a bit curious.
Some of these images just look like aliens they would have already had pictures of. However, two stand out as potential easter eggs - the picture on the middle left looks unmistakably like Spock, and the human on the bottom left looks like they could be a production worker or a favorite musical artist.
However, Memory Alpha and a simple Google Search don't seem to turn up anything. I'm intrigued to know what history, if any, is behind this graphic.
An update: According to S2 E10 Sanctuary, the guy below the Ferengi (not shown in this screenshot) is stated to be Plix Tixiplik, who had previously shown up in TNG, further affirming them being previous Trek actors.