In general terms if each photo is around mb for a full resolution photo should give you around photos. Though again if you shoot higher o Hi, .
Choosing the Best SD Card for Video – Understanding All the Numbers and Symbols on SD Memory Cards
How many pictures can my memory device hold? Photos - Compressed (JPEG % quality) Images per card. SDHC/microSDHC 4GB to 32GB FAT Number of photos you can store: RAW What memory card size are you using? How many megapixels is your camera? Number of photos you can store: Note: this calculator is a guide. Values are based on those published by Sandisk.
Fred. On a Nikon D my RAW images are approx 12 Mb each and I reckon to get images on a 4Gb compact flash card. As noted above the number of images depends on the size of output image you select from the menu options.