Images can be resized using mogrify from the ImageMagick suite:
`mogrify -resize 256x256 *.jpg`
But this will resize images so that the largest dimension is 256px, including images that are smaller than 256px to begin with (like 100x100px avatars).
How can I exclude the smaller images from being affected? i.e. I want the largest dimension to be no more than 256px
(Preferably I will be able to do this with ImageMagick suite, or at least without installing anything additional).