If this was my car, I would
- 1. Jack it up high enough to get the wheels off and support the rear suspension at the struts or springs or shocks or whatever you have with jacks stands .. to synthesize the wheels being on the ground.
2. Take the back wheels off.
3. Put a straight edge, vertically, on the front surface where the wheels bolt up and note how the straight edge lines up with the top of the wheel well. You may even want to measure from the outside lip to where the top of the straight edge is
If something is bent, worn out, misaligned, the straight edge is going to line up more inboard on the passenger side (that is okay)... and the driver side will be further out, causing some of the rub.
While those wheels are off, you might even want to measure from the rear face mounting surface of the wheel to the rear most edge of the tire and make sure they are both the same. Very remote, but you can eliminate the possibility of wheel offsets not matching.
The pictures are hard to tell, but, yes, I agree one side is lower than the other.
You might have spent all your budget on the 20s and tires, but a trusted alignment shop can check out your suspension and all this other stuff.