I once used this script to resize and rotate a bunch of images. It reads the EXIF tag for orientation, then rotates the image appropriately and resizes it to either 1024x768 or 768x1024. All of this uses ImageMagick. Consider this public domain.

#!/bin/sh
TARGET_PATH=$1
if [ ! -d "$TARGET_PATH" ] ; then
    echo "$0: Not a directory: $1"
    exit 2
fi
shift
while [ -n "$1" ] ; do
    if [ ! -r "$1" ] ; then
 echo "$0: Cannot read file: $1"
 exit 1
    fi
    ORIENTATION=$(identify -format '%[EXIF:Orientation]' $1)
    case "$ORIENTATION" in
 "1") # Rechtop
     convert $1 -resize 1024x768 $TARGET_PATH/$1
     ;;
 "3") # Ondersteboven
     convert $1 -rotate 180 -resize 1024x768 $TARGET_PATH/$1
     ;;
 "6") # Kwart slag tegen klok in gedraaid
     convert $1 -rotate 90 -resize 768x1024 $TARGET_PATH/$1
     ;;
 "8") # Kwart slag met klok mee gedraaid
     convert $1 -rotate -90 -resize 768x1024 $TARGET_PATH/$1
     ;;
 "*")
     echo "Whoa! Unknown orientation: $ORIENTATION. (Was it reflected?)"
    esac
    shift
done