mogrify

Editing (resizing, format converting, compressing) images in the command line with ImageMagick (mogrify, convert)

Resize all tif images in the current directory:

mogrify -resize 25% 25% *.tif

Resize all jpeg images in the current directory to a width of 614 pixels and keep the image ratio constant:

mogrify -resize 614 *.jpg

As above, but resize the hight to 614 pixels:

mogrify -resize x614 *.jpg

Convert all bmp imgaes in the current directory into tiff images:

mogrify -format tiff *.bmp

Compress all tiff images in the current directory with ZIP compression: