But I also have private Moodle installation 3.2 (http://labs.fpv.umb.sk/~milias/my_moodle/moodle/), and "HTML editor with file picker" is not working - the Essay question in Quiz does not accept picture. Maybe I did something wrong in Moodle setting, or could it be a bug ?
Ah, I see ! The proper response format is "HTML editor with file picker", and the essay accepts (drawn) pictures. This is working fine with Moodle 3.3, what is our university installation (https://lms2.umb.sk/). My students can draw chemical formulas and schemes now.