Partimage is a Linux utility which saves partitions having a supported filesystem to an image file. Most Linux and Windows filesystems are supported. The image file can be compressed with the gzip / bzip2 programs to save disk space, and they can be splitted into multiple files to be copied on CDs / DVDs, … Partitions can also be saved across the network using the partimage network support, or using Samba / NFS.
Partimage will only copy data from the used portions of the partition. For speed and efficiency, free blocks are not written to the image file. This is unlike the ‘dd’ command, which also copies empty blocks. Partimage also works for large, very full partitions. For example, a full 1 GB partition can be compressed with gzip down to 400MB.
[ source partimage.com ]