I thought the first example were your legs I was like god damn they look good. I know you don't care about my preferences...
Weight training and genetics.
Quads are worked during... Squats, deadlifts and running sprinting. If you have STOPED working out but still eating the same... At first your muscle may look a little bigger from glycogen build up which is water and sugar build up in the muscles from them not being worked as they normally do... They look bigger for a time (not as cut obviously)
I think you've asked this question before and I recommended long cardio sessions to break down the muscle over time and cut the weight training. Let me give you some supporting information.