I have a brand new Canon T3i digital camera. Went from the same camera that used film to digital. I'm a little behind the times. Anyway, what does reformatting the SD card do and do I HAVE to do that at all? Do I have to download the software disc onto our computer in order to lownload a picture or several from SD card to say Facebook or just our desktop for use on the computer? I'm kind of confused. Any help is appreciated.