Installing a disc image on an SD card of larger size

I have forgotten what happens when you install a disc image of size xGB on an SD card of size yGB where y>x. Is (y-x)GB of the card wasted? In particular, in the case: Raspberry-Pi Risc OS disc image (x=2, I think) and y=4 or 8 say.

Same question, but for NOOBS?

For RO—yes, the space is wasted. With an OS that understands partitions, you could create an asditonal partition or partitions in the unused space.

The alternative is to invest in a copy of Ben Avison’s SystemDisc application (about a tenner) and you can then set up an SD card of any size that uses all of the space for RISC OS, apart from say the 64 MB allocated to the hardware boot partition. Works a treat.

Edit: I should add that you then have to copy all the files on to the card yourself, but you will have the files anyway from the 2GB disc image you are already using.

Thanks, David and Chris, for your quick replies.
I have Piccolo’s SystemDisc, which I usually use for creating an SD card for RISC OS. I, also, recommend it as it is easy to use and well worth the tenner.

However, I am helping someone set up such a card who has a Raspberry-Pi, but has no RISC OS computers; and we are many thousands of kilometres from my home. I have brought with me 2 SD cards for RISC OS on Raspberry-Pi and 2 USB sticks with extra software. I was wondering which method would be best for someone new to RISC OS and wanting to learn about it. Bearing in mind your answers, I think we will use SystemDisc.