This small extension introduces support for Data URI scheme to GameMaker HTML5 target, allowing you to use "data:<type>[;base64],<data>" format instead of normal URLs in most spots, though most handy for loading externally generated sprites.
Setup: Import the extension. That's it. You can now use Data URIs.
All thanks to some incredibly strange code that patches some built-in function 3 calls deep. Most people wouldn't do that to themselves.