Yes. No problem. Unless the camera is really old. Just try it it won't hurt it.
Yes, 512MB is 1/4 the size of 2GB.
512MB equals .5GB or 1/2GB.
200
It depends upon the MP of your camera. The more the MP the higher the quality of the photo, and so the no of pictures that can be stored reduces. For ex, for a 2MP camera, you can store 2379 photos on a 2GB card, whereas for a 8MP camera you can only store 635 photos.
a 512mb graphics card is a very general statement. 512 megabytes is pretty bad for a graphics card, but it is doable. chances are the graphics card itself is bad, not necessarily just because it's 512mb.
fat instead of ntfs
It depends on the camera.
417
512 TO 20,000
No. 2 Gb is 2048 Mb. 2Gb is four times the memory of 512Mb.
it depends on what kind of camera and how much memory 2gb 12.99-16.99, 4gb 16.99-22.99 and so on
I would suggest you go for the 2gb ram and 512mb vcard. It has more performance. 2gb can run Vista and windows 7, while 128mb vcard you'll have trouble on running on these current systems. 128mb vcard is not worth it for a 3gb RAM nowadays. unless its a ddr3 and supports cuda and other nvidia or ati stuff, which is impossible on today's tech. Also, if need be, you can upgrade the RAM from a 2GB to more. It's harder to upgrade a GPU, and more expensive as well.