This is for samsung, dont know how to do it on other phones like apple or huawaii.
Download a photo on google from a creature you want ( or take a picture of your drawing/art).
I am gonna use this Diabloceratops.
Go to edit the photo, first click on the white arrow too go too filters. Scroll to the back and the click the button with the red arrow.
Download this filter and apply it.
Click the button with the white arrow, then the red arrow and change it as low as possible.
Know click the red arrow and change this also too lowest as possible.
( Step 6.)
Change the size of the picture if you want mine know is like this
Go and make your custom creatures with custom Silhouttes