We can mask a png image over any other image with rotation and proper alignment. Let say for example, if we need to replace the human face of an image with another face, then we need this type of masking. There are various ways and command within imagemagick but I found this command combination very suitable:

Main image: myimage.jpeg New face: mask.png rotation angle:15 degree X position: 200px Y position: 100px face width: 40px face height: 50px

Command:

convert myimage.jpeg \( mask.png -resize 40x50  -background none -virtual-pixel background +distort SRT 15 \) -geometry +200+100 -composite newimage.jpeg

This command will also remove black background around replaced png. Hope this will help someone.