Did you ever blow up a picture file and see all the little colored pixels? This is a raster graphic. Web graphics and digital photos are stored as raster graphics.
Vector graphics are made up of paths representing lines and shapes instead of pixels. Vector graphics can be enlarged without losing their sharp quality.
You have a digital camera and it creates camera raw files. Many different camera raw files exist and you can only open them if your program supports both the file type and the specific camera model.
Popular graphic image extensions are .TIF, .PNG, .PSD and .JPG.