I don't see anything seriously wrong .
I'd give the cylinder a light hone , just to clean/level any possible high spots .
Then , use an exacto type knife ( very sharp point ) and score top and bottom of each ring were it meets the piston , all the way around . Drop the piston , top down , into some penetrating fluid or diesel oil or even gasoline . Let that soak in along side the rings before gently trying to free them from their landings .
Maybe have to repeat the 'procedure' before complete success .
Once the rings have been removed and cleaned , clear the landings and reinstall the rings . (edited)