Using Adobe Photoshop, create an avatar or some sort of character. Next, design or clip different accessories/features onto different layers. Group the accessories into categories (for example: I used hats, glasses, different mouths, and different backgrounds- so each would it’s own layer and grouped accordingly.) Finally, download the photoshop composition composer master file from the internet (JXS file) and run the script. From there it will generate as many variations as possible. 

Tutorial link for the script:
https://www.youtube.com/watch?v=_Z99COgONYQ