We've had issues with server space in the past that have required some image-limiting rules, but from what I understand there isn't a technical rule against posting that many images.
However, I would caution you against posting that many pictures for your viewers's sake. 50 high res photos is a lot to scroll through. I would advise you to make collages/group photos with several MOCs per pic. You could try grouping the Brickheads loosely by theme (e.g. all of the Luke Skywalker variants in a single pic).
Also, props to you on making 50 different Brickheadz. That's no small feat.