I can, same scenario as you, also noticed at uni for the same reason. I see it as a glow, and thought initially it was just after-image, but it's not the same in non-living objects, and if i think about it i can see colours. I don't know what the colours "mean" but i have seen very murky-gritty-looking ones in people not long for this world. Have you ever noticed that plance have them too and their light is much purer looking?

I don't know about the aura photos and i'm skeptical of writings on what it "means" as i can see them and don't know what it means so why would someone else know, iykwim. I might be the only skeptic around who sees auras and so on. LOL.

Bx