I think NEJE-V5.3.5 needs a button in the SET SIZE section so that the image proportion can be unlocked or locked. Just like LaserGRBL has them with a lock icon. Currently it does not allow custom resizing, since when you place the measurement and click OK, it automatically resizes to a measurement that you don´t want the engraving or cut to have.
Thank you for your suggestion, we will remind you here when new software is available, as the NEJE Master series has been slowly updated, this may take longer.