howtos for various backup systems…
Replace sdX with your SDcard (check fdisk -l)
dd bs=4M if=/dev/sdX | gzip -c9 > /home/your_username/image`date +%d%m%y`.gz
2. terminal:
watch progress
Restore:
gzip -dc /home/your_username/image....gz | dd bs=4M of=/dev/sdX