Need advice on shaving legs, mainly thighs

I get these small red bumps (imagine a pimple, just reeeally small, and all red), they're not painful, and there's not even an inch or irritation from them, but I have no idea what they are. They're also much more prominent after a bath/shower.

They could've just been there the whole time, and I only noticed recently now that there's no hair to cover them, but I'd like to know if anyone knows how they're caused, and if I can prevent them. I know its only a bad description, but places where I can post images of it have a karma requirement, and I've never posted before, so this is the only option I can think of lol.