A camera is more powerful than a cell phone because it has much more data to treat, but they work just the same.

When we're talking about the internal buffer of a camera or cell phone, we're talking about RAM i.e. high-speed memory that does not keep its contents when the power is turned off. It's linked directly to the image processor.

The CompactFlash card is NAND Flash memory that keeps its data when the power is turned off, like a disk. It's much slower to write than RAM. It's seen by the system as being a disk and is formatted in FAT32 usually. Plug your telephone or camera into a computer via the USB port and you will see it as a hard drive.

In your cell phone you have the internal memory buffer plus TWO Flash memory devices - the removable card and a non-removable built-in memory. When your cell phone takes a picture it stays in RAM while being treated then it gets written out to the fixed Flash drive automatically. If you want to get it out on the removable Flash drive you have to move it.

In a camera you have just the internal memory plus the Flash card. The camera treats the image in RAM then writes the result out to the Flash drive.