Remove Black Space

[magick]

Use -trim to remove borders from your image. Add -fuzz if the border is not of uniform color.

[anthony]

If you also specifically add a 1 pixel black border to the starting image before using -trim, then you can gurantee that it will only trim black.

This added black border becomes especially important which you also use a -fuzz factor, otherwise you can not be sure what color the color comparision function is comparing against. It may not be pure black
for example.

See IM Examples, for Image Trimming with a specific color.
http://www.cit.gu.edu.au/~anthony/graph ... trim_color