These are from somewhere in the NetBoot Mac OS 9.2.2 disk image. I'm not sure which file they came from. The Apple campus image is also somewhere in this disk image, but not the iguana flag.
I realize this is a bit off-topic, but these discoveries have indeed stemmed from the PEX ROM. If a Mod wishes to move these into a new thread, I would be okay with that. Actually - should we put all of the team pictures into the wiki and document where they came from and how to make them appear (if possible)?
This picture came from a 7.6.1 installation but appears to have come from an erased file on the hard drive. When I mount sheepshaver's hard drive image and create a new disk image from it with Disk Utility, this picture is not included in the new disk image. I think that the installer may have copied an extension that contains this picture to the hard drive and then deleted it.
I think teams get a lot of stuff done if they're serious all the time, and they have a lot of creativity if they goof off a lot. Apple's edge has always been creativity and I think some of these pictures demonstrate where it came from!