The following comes from Jason Scott and is posted here with permission under the Creative Commons Attribution-ShareAlike License.

The script expands a zip or rar archive of images, makes thumbnails, and compiles the thumbnails into a single JPG to represent what's in the archive. Requires ImageMagick.

Code:

#!/bin/sh
# GALLERATE: Turn a zip of images into a gallery.
# From Jason Scott. http://ascii.textfiles.com/archives/000137.html
if [ -f "$1" ]
   then
   rm -rf .galleryworld
   echo "[%] Preparting to squat out $1...."
   mkdir .galleryworld
   cd .galleryworld
   unzip -j "../$1"
   unrar e -ep "../$1"
   echo "[%] WHY DOES IT HURT!!!!"
   montage +frame +shadow +label -tile 7 *.JPG *.GIF *.gif *.jpg *.bmp *.png *.PNG *.BMP "../$1.jpg"
   cd ..
   rm -rf .galleryworld
   ls -l "$1.jpg"
  else
  echo "No such file, assmaster."
fi

Usage:

GALLERATE [file]

where [file] is the zip or rar archive of images to be processed.