Well, with pictures left in, my results are:
epub 2 406 KB
azw3 2 422 KB
Hm, it seems that I'm doing something wrong when removing pictures. After I removed them, the size of epub file was a lot smaller (2 406 KB to 1 594 KB) but the size of azw3 stayed almost the same (2 422 KB to 2 218 KB).
What I would like to achieve, is azw3 file of size around 1.5 MB (without pictures), but no matter what I do, I can't make it