Can i change one of my teams? If so how?
Also how come some players have pictures and others dont?
Hello, welcome to OSM and forums.
Yes! You can change your team by resigning from your current team and league, then you can pick a new team in a new league. (please note that you can not pick a team or rejoin a league which you resigned from).
For your second question; this is because currently OSM has not secured the right to make use of those players photograph.