The is just ONE example how you can do it.
First open 2 paint program. Open one of the picture file on one side.
Block how much you want and click on copy
go on the left side and pull on the block and make it to a size you want.
Paste the picture on the left
Open another file on the right and block and copy what you want
Paste that one in also
click on the picture and move it to the right
This is a very inefficient way to do it though but its simple enough.