Do I bear sin if my friend revisits bad pictures I previously sent him, or sends them to others, after my repentance, and does absolving myself before him relieve me of responsibility?

The questioner is congratulated on his repentance. He must strive to remove the forbidden images he sent to his friend and ask his friend to delete them. If the images remain in circulation after he has made an effort, then there is no sin upon him, for Allah does not burden a soul beyond its capacity. The repentance of one who repents from a sin is accepted, and the persistence of its effect does not harm him.