I seem to have run into an error.

The error gives the following message.:

Failed to load mods: 16-bit image channels are not supported: RampantFixed/graphics/icons/thief/crystal-drain.png

I have tried most things I can think of, such as deleting the mod and reinstalling it, etc. as well as Factorio etc. and the like.
To no avail thus far.

I also did not find any fix on the internet as a whole or on the forum of factorio and this mod portal in specific.

To any and all enjoy the rest of your day, and thanks in advance for any and all help!

Unfortunately, I can't help.
I don't get this error, and image editors say it's 32-bit
Alternatively, try replacing the file with another image, maybe that will help.