Let’s say you have an image with a following dimensions:
$ identify logo.jpg logo.jpg JPEG 400x178 400x178+0+0 8-bit sRGB 55.6KB 0.000u 0:00.000
and white background as for an example:
However, what we need is in image with a white background with 400×200 pixels dimensions. What we need to do in this case is to create a new 400×200 white canvas and center place our existing image it it. For this an Imagemagick provides a simple solution:
$ convert logo.jpg -gravity center -background white -extent 400x200 new_logo.jpg $ identify new_logo.jpg new_logo.jpg JPEG 400x200 400x200+0+0 8-bit sRGB 57.1KB 0.000u 0:00.000
