do you think i can morph images together and combinate a bones action :
for exemple , i try to make an man fly and i have drawn several positions, but not enough to make my guy semm real :/ so between both can i create a transition as morphing ?
Moho really isn't designed to work like that. However, with switch layers you can interpolate (morph) between different drawings, so that may be one way to get it to work. The problem is that this feature of switch layers is kind of limited - each layer in the switch group has to have the exact same number of points. It was intended as a way to smoothly move a mouth from one position to another, and even though it might work for what you're describing, I think it will be awkward.
PNG files do act as layers - Image layers. However, Moho cannot interpolate between them. With vector layers, Moho knows more information about the structure of the artwork. With image layers, all Moho sees is a random collection of colored dots (pixels).