UsersController's actionUploadUserPhoto and actionCropUserPhoto with Element API Can you use the Element API plugin to utilize UsersController's actionUploadUserPhoto and actionCropUserPhoto methods?
Not natively.  The Element API plugin provides a "read only" API to Craft's controller endpoints.  Both actionUploadUserPhoto and actionCropUserPhoto request POST/write requests.

You could fork it and add POST/write functionality to the plugin/API, though.