Using mogrify to -crop and -resize images

A quick reminder to myself for later on: when treating documents scanned in with the Canon scanner in greyscale at 150 DPI, resize the NZ and Aus diary pages slightly before uploading them to the website.

A good way to do this is with ImageMagick's mogrify command (since it can handle batches of files at a shell prompt). To resize the images, use mogrify -sample 70%x70% *.jpg. To cut off the bottom inch or so of noise caused by the diary page being shorter than A4, use "mogrify -crop 869x1080+0+0 *.jpg" (this leaves the very bottom of the page in the completed jpg file). Since mogrify rewrites files in place, there is no need to move files around afterwards.

The ImageMagick website is here.