When you have lots and lots of photos to process you will want to set aside GIMP and use ImageMagick. There are binary versions available for Unix/Windows/OSX and source code versions available for those of you who prefer to compile your own. This is Open Source, free for you to use software.

Directions for installing ImageMagick (* see note for OSX at bottom of post )

Now I’m old school and often work from a command line or terminal. Those of you who would rather have a graphical interface might want to check out JMagick, a Java interface for working with ImageMagick. This is just an interface, ImageMagick will need to be properly installed first for the interface to work.

Once you have it up and running you can batch process your images.

For instance if you want to create thumbnails for 100 jpg images:
Open up a terminal window ( Command in Windows Terminal in OSX )
cd to the directory with the images
type at the command prompt and hit enter
convert *.jpg -resize 100 thumbnail%03.png

This will convert all files ending in .jpg in this directory to png files that have a width of 100 pixels and are named thumbnail000.png to thumbnail099.png.

You can convert jpgs to png to gif and any which way between them.

You can do any of the following conversions to the files:
[-adaptive-blur • -adaptive-resize • -adaptive-sharpen • -adjoin • -affine • -annotate • -antialias • -append • -authenticate • -auto-orient • -average • -backdrop • -background • -bias • -black-point-compensation • -black-threshold • -blue-primary • -blur • -border • -bordercolor • -borderwidth • -cache • -channel • -charcoal • -chop • -clip • -clip-mask • -clip-path • -clip-path • -clone • -coalesce • -colorize • -colormap • -colors • -colorspace • -combine • -comment • -compose • -composite • -compress • -contrast • -contrast-stretch • -convolve • -crop • -cycle • -debug • -deconstruct • -define • -delay • -delete • -density • -depth • -descend • despeckle • -displace • -display • -dispose • -dissolve • -distort • -dither • -draw • -edge • -emboss • -encoding • -endian • -enhance • -equalize • -evaluate • -extent • -extract • -fill • -filter • -flatten • -flip • -flop • -font • -foreground • -format • -format • -frame • -frame • -fuzz • -fx • -gamma • -gaussian-blur • -geometry • -gravity • -green-primary • -help • -iconGeometry • -iconic • -identify • -immutable • -implode • -insert • -intent • -interlace • -interpolate • -label • -lasso • -lat • -layers • -level • -limit • -linear-stretch • -linewidth • -list • -log • -loop • -magnify • -map • -map • -mask • -matte • -mattecolor • -mask • -median • -metric • -mode • -modulate • -monitor • -monochrome • -morph • -mosaic • -motion-blur • -name • -negate • -noise • -normalize • -opaque • -ordered-dither • -orient • -page • -paint • -path • -pause • -pause • -pen • -ping • -pointsize • -polaroid • -posterize • -preview • -print • -process • -profile • -quality • -quantize • -quiet • -radial-blur • -raise • -random-threshold • -recolor • -red-primary • -regard-warnings • -region • -remote • -render • -repage • -resample • -resize • -reverse • -roll { • -rotate • -sample • -sampling-factor • -scale • -scene • -scenes • -screen • -seed • -segment • -separate • -sepia-tone • -set • -shade • -shadow • -shared-memory • -sharpen • -shave • -shear • -sigmoidal-contrast • -silent • -size • -sketch • -snaps • -solarize • -splice • -spread • -stegano • -stereo • -storage-type • -strip • -stroke • -strokewidth • -support • -swap • -swirl • -text-font • -texture • -threshold • -thumbnail • -tile • -tile-offset • -tint • -title • -transform • -transparent • -transparent-color • -transpose • -transverse • -treedepth • -trim • -type • -undercolor • -unique-colors • -units • -unsharp • -update • -verbose • -version • -view • -vignette • -virtual-pixel • -visual • -watermark • -wave • -white-point • -white-threshold • -window • -window-group • -write]

There are hundreds of detailed examples here: ( ImageMagick Examples )

*Note for OSX installations:
You will need to edit your .bash_profile file. It is in your home directory, and add the following lines.

#ImageMagick Stuff
export MAGICK_HOME=”/usr/local/ImageMagick”
PATH=$PATH:$MAGICK_HOME/bin
export PATH
export DYLD_LIBRARY_PATH=”$MAGICK_HOME/lib”
# end Image Magick Stuff

Save the file, close the terminal window and open a new one to cause .bash_profile to run.

I use it when I make major updates to my website or am updating links. I can have it search for the old link and replace it with the new link. (or any other piece of text you’d like to change).

It puts the altered files in the working directory and leaves the originals unchanged. It also prints to the screen the file name and line number of any changes made.

findAndReplace.pl

It is a PERL script, it will ask you for the old and new strings and changethe files in the directory in which the script is located.

chgfilename.pl