You need to plan for losing your main partition and any other partition on the same device, i.e. you cannot rely on recovery partitions. I suggest a combinatio

You need to plan for losing your main partition and any other partition on the same device, i.e. you cannot rely on recovery partitions. I suggest a combination of booting suitable disk imaging tools from a USB pen drive (both for creation and restoration of your disk images) and storing disk images on a large external USB drive or on a network server, so that the former is small, disposable and practically read-only and the latter doesn't need to be bootable.