SD High Capacity Storage Media
Compact Flash is the media of choice for digital SLRs. However, if you are shopping for a late model compact digital camera, you'll find that the SD card is more common because the card takes up less space on the smaller form factor camera body.
Certainly you know how the capacities keep increasing on all media cards in your digital camera and mobile phones, but did you know a huge leap has been made in the smaller ones out there?
The SD card has become High Capacity (SDHC). Cards 4-32 GB are considered high-capacity. That's the good news. The bad news is you can't use them in your SD devices unless your devices are SDHC. The good news is if you have a new device that uses SDHC cards, your old SD card will work in it.
Image Source: SD Association (http://www.sdcard.org/sdhc/index.html
The SD Association provides the technical specs if you really need them:
http://www.sdcard.org/about/sdhc#1