How to insert smaller images over bigger (webcam frames, realtime stream)?
For example, fake mustache, glasses, funny hats... I can detect faces and eyes etc in the frame and figure out location for placement, scaling etc, but how to actually 'draw', or put it on the frame?
Ah thats fairly simple. You will need the image, a mask and then overlay both images. The adding images tutorial will be a good start.
How to handle .png files wwith built in transparency?
Please put in some effort, the first google link will tell you that exactly ...