can memory cards have an image (such as SD cards and the likes)

i was just wondering, do SD cards and CF cards, etc have 'images' like a CD or a DVD has a disk image?

Why not. Disc images are just a software thing after all. If you have the software to read and write them, you have an image.

how common is it for technologies to use memory card images if you know,

i know that CD/DVD images are popular with many technologies like the play station, computers, DVD and CD recorders and players for television sets, etc

Ever seen a digital camera...

There is almost no use for imaging a memory card, perhaps archiving and compressing a snapshot but the actual bit per bit placement of a file is not really that important that's what a file system manager is for.

I could see some isolated need for it if you did a project using memory cards that didn't have any file system and used fixed offsets for file access. USB drives can be made bootable now so backing up bootable USB stick would required imaging in order to read the boot sector or if you wanted to burn that bootable drive image to multiple flash cards.

Any block addressable storage medium can be imaged using basic commands in linux such as DD