This code is from Chimeric, here is the original. That's only a copy&paste because it gives me many ideas:
All it takes is ImageMagick, Firefox the Firefox Fullscreen extension tied together with a little bash script1). The Fullscreen Firefox extension can be configured to hide the tabs/scrollbars when switching Firefox into fullscreen mode via F11. That comes in real handy because you don't have to worry about how to remove these things from the screenshot later. Here's the script.
#!/bin/sh # @author Michael Klier <chi@chimeric.de> # # small script to create a series of website screenshots DATE=$(date -I) FX_BIN=/opt/mozilla/bin/firefox IMM_BIN=/usr/bin/import if [ -f $1 ]; then URLS=$(cat $1) else URLS=$1 fi mkdir ${DATE} && cd ${DATE} CNT=1 for URL in $URLS; do if [ ! -n "$2" ]; then PREFIX=${DATE} else PREFIX=${DATE}-${2} fi if [ $CNT -lt 10 ]; then FNAME=${PREFIX}-0${CNT}.jpg else FNAME=${PREFIX}-${CNT}.jpg fi $FX_BIN $URL && sleep 5 $IMM_BIN -window root -display :0 -resize 1024 $FNAME CNT=$((CNT+1)) done