how do i duplicate texture to paint slots?

Support Materials and Textures
#1

i want to paint a character and want to do it with multiple layers and then bake the textures. is it possible?

#2

2016-12-28 19_12_29-Blender_ [C__Users_udi_Desktop_growlith_growlith.blend].png911×709 43 KB

pic related i want to add exactly same texture so i can see my previous one when i paint over