====== ImageMagick Tricks and Snippets ======
===== create a stack of images =====
e.g. all images named inputimage01.tif .. inputimage99.tif in one folder should be converted to one image-stack
  convert -adjoin inputimage*.tif outputimage.tif
"-adjoin" is optional, if outputimage-format can contain multiple images
===== resize image =====
- percentage
  mogrify -resize 50% image.jpg
- to maximal size (all images in current folder)
  mogrify -resize 256x256 *.jpg
- resize and change bit-depth
  mogrify -resize 2994x2994 -depth 8 *.tif
===== shave image =====
shave off at the image edges to leave away unnecessary parts
  mogrify -shave <width>x<height> *.tif
===== crop image =====
==== central crop ====
  mogrify -gravity Center -crop 50x80%+0+0  *
crops image  to 50% of width and 80% of height
==== very small ====
  mogrify -shave 1750x250 -chop 450x0 -crop +0-250 +repage *
modifies image {{:imageprocessing:imagemagick1.jpg?75|}} into smaller, cropped image {{:imageprocessing:imagemagick2.jpg?29}} (rescaled for illustration purposes)
  "-shave 1750x250"
shaves 1750px left/right and 250 pixel on the top/bottom
  "-chop 450x0"
chops off 450 pixel on the left side
  "-crop +0-250 +repage"
chops off 250 pixel at the bottom side and repages the canvas of the image.

all info is taken from [[http://www.imagemagick.org/Usage/crop/|the IM help]]
===== convert =====
all images in folder from png to jpg
  mogrify -format jpg *.png
all images in folder from jpg to eps
  mogrify -format eps *.jpg
create a movie out of still images
  convert *.jpg movie.mpg
===== create a listing =====
to create a listing of the filenames with their size into a textfile use
  identify -format "[\"%f\",%w,%h];\n" *.jpg > listing.txt
[via [[http://groups.google.com/group/hugin-ptx/t/f4c3467fec4794d7|erik krause]]]
===== make a montage of a bunch of images =====
Take a directory full of images and make a nice montage, polaroid-style

  montage *.tif -bordercolor yellow -background red \\
      +polaroid -gravity center -background none -geometry -50-50 polaroid.png

{{ :imageprocessing:polaroid.jpg?256 |polaroid.png}}

Keep in mind that this only works for not very big amounts of not very big images, so "resize" them first. The resulting image is really big, so you might need to resiye that too...

You might also prefer to change the -bordercolor to "white" and the -background to "black", here it is yellow and red for demonstration purposes...

  montage *.tif -thumbnail 256x256 -bordercolor yellow -background red +polaroid \\
      -gravity center -background green -geometry +1+1 polaroid-green.png

{{ :imageprocessing:polaroid-green.jpg?256 |green background}}

makes 256x256 -sized thumbnails first and adds a small (1x1) border around each image, so they line up nicely. Substitute "yellow" with "white", "red" with "black" and "green" with "none" to have a useable result...

adapted from the [[http://www.imagemagick.org/Usage/montage/#overlap|ImageMagick help]]