you're probably going to want something that can take advantage of the features like pressure sensitivity and other pen functions. try smth like krita, firealpaca, or medibang paint. i've used mostly firealpaca of those three and i'm p sure it's the least sophisticated of the bunch. i'm assuming you got a cintiq for drawing so those would probably be a good fit, not sure of good free software specifically for photography tho if that's smth you need. if it is for drawin tho, down the line, i would defo recommend clip studio paint