Align 2D Molecule to horizonal / vertical axis?

When rendering an image format I would like the molecule to take up as much physical space as possible.

I would like the longest length of a 2d molecule to align to either the horizontal or vertical axis of the image so that it is displayed as large as possible?

How can I do this please?

If you specify the image size, Marvin will scale the molecule image for this dimension (choose the best fit). e.g.:

molconvert png:w500,h500 morphine.mol -o morphine.png