the Cube screenshot is from PCSX-Redux's PS1 BIOS, released under
MIT license. The cube is machine-generated so probably doesn't fall
under copyright. Therefore, no copyright is claimed and restrictions
of copyright would not apply.

The photo of the PSOne Slim is from here:
https://commons.wikimedia.org/wiki/Category:PS_one#/media/File:PS_One_with_LCD.JPG
Released under license: CC BY-SA 3.0
More information including about the owner is on that web page.
The version distributed by Libreboot has been modified; the image
has been downscaled and compressed for the web. The original high
resolution image can be found at the above link.