Original map screenshot Easter egg
From Halopedia, the Halo wiki
The original map screenshot Easter egg is an Easter egg in each of the multiplayer maps released in the Halo: Reach Anniversary Map Pack. Each multiplayer map has included a screenshot of the original map it is based on. It is recommended to find them in Forge.
On Battle Canyon, the screenshot of Beaver Creek can be found on the underside of the structure protruding from the top of Red Base (labelled "Red Roof"), at the end of the long red light.
On Breakneck, the screenshot of Headlong can be found on the seawall, facing the water, near the turn on the southern part of the map.
On High Noon, the screenshot of Hang 'Em High can be found on the Blue Base side of the map, under the area labelled "Blue Bunker", right beside the hologram, and is part of the bridge in the area labelled "Lower Catwalk".
On Penance, the screenshot of Damnation can be found in the room labelled "Upper Pump Room". It is located on the darker side of the pipe that is attached to another pipe.
On Ridgeline, the screenshot of Timberland can be found in the area labelled "Upper Red Base", on the eastern gravity lift's walls.
On Solitary, the screenshot of Prisoner can be found on the bottom of the eastern catwalk under the broken window, in the area labelled "2nd Floor".
This collection of Easter eggs may be inspired by the screenshot of Hang 'em High found in the Halo 2 multiplayer map Tombstone.