Can you spot any errors in this?
The first picture is what the switch currently looks like with the dimmer switch on it. The 2nd picture is the same same thing, but what it looked like before putting the wires to the dimmer switch. Thank you in advance

Wish I could see more of the switch but it looks fine to me, is it not working?

I would rather see a pigtail added so as to have only one wire under the screw?

I would like to know where the main feed conductor is, first.

Is it in the ceiling? Is the switch part of a switch loop or is the power being brought to the switch and then continues up to the fixture.

On my system, in picture #1, I see a red conductor. Where is it coming from? Where does it go? What is its purpose?