Questions & answers
libreboot, and blank background?
I never found any writings about this topic online, even though the answer is quite straight forward. So yes, you can have a blank background, and remove the picture from the image file. The documentation on libreboot.org only describes changing the current background, but it's both simple and possible to remove it completely.
I currently use a Lenovo Thinkpad T400, running libreboot instead of stock BIOS.