PiExt
Backup and restore tool for Raspberry Pi systems
...Image creation is also available via the command line (CLI).
Instead of storing the complete filesystem partition, PiExt stores only the sectors currently used by the filesystem. The data is compressed on the fly using Zstandard (ZSTD). The MBR and BOOT are stored separately.
The first image created in an image folder automatically becomes a Base Image. Further images are created as Differential Images based directly on the Base Image.