Photoshop help

Hi clever computer people. My problem is that i have 3 pictures from google image search that are different sizes that i want to join together. What i want to do is have my 3 sporting hero's in one picture and then mess about with it a bit in photoshop. What do i use to join the pictures together? Is is it even possible? :?

Thanks

not really sure but I know you can crop em close to each other :?

yeah, i know its possible....but i just started learning photoshop so i dont know if i can explain it