The main image of this card is 3rd of May Street. Naming streets after that date in Poland seems to be fairly popular since it references the 3 May Polish Constitution of 1791. It was the second ever written constitution in the world, after the American one.
I will point out that when I bought my Rzeszow postcards, the shopkeeper was so excited that I was buying them that she gave me this one free. Her store was located on this street but was moving to a different location in a few weeks.