mogrify

Tool that allows making operations on multiple images ie. resizing, cropping, flipping, adding effects. Replaces the original file.

Resize all jpg images in the folder to 50% of their initial size:

mogrify -resize {{50%}} {{*.jpg}}

Resize all images starting with DSC to 800x600:

mogrify -resize {{800x600}} {{DSC*}}

Convert all png images in the folder to jpg:

mogrify -format {{jpg}} {{*.png}}

Halve the saturation for all image files in the folder:

mogrify -modulate {{100,50}} {{*}}

Double the brightness for all image files in the folder:

mogrify -modulate {{200}} {{*}}