I didn't notice any difference at all, so no screenshots. Really though, I binded the two to different keys, moved around pressing them, and there was no difference.
Bloom, is an effect that simulates to I pull ahead surrounding the sun or other intense light sources. Im not sure, but it appears to "make" the sunshines entering through the windows... But in interiors nothing its changed.
I've noticed that certain effects, if you change them in game, don't seem to take effect until you reload the level or do a quickload or something.
For example, if you change the gravity (sv_gravity 200) during a level, gordons gravity changes but the physical objects in the level stay the same unless you load or restart the level.
Anyone else notice this? It might be the same for other effects too, like the bloom?
I've noticed the bloom mostly on the coast level where you are driving through a dark tunnel and entering the daylight.....Almost makes you have to squint....