The following information for photo images is a guideline, the number will vary based on several things, such as camera model, internal file size, compression settings, what you have chosen for resolution and compression mode settings and finally, JPEG or .JPG (is a compressed file) compression will result in different file sizes based upon picture complexity…
MP=Megapixels: MB=Megabytes, GB = Gigabytes
This approx. number of photo images can be used on these 2 different size SDHC Memory Cards on 4 different size cameras - 6MP, 8MP, 10MP and 12MP. The SDHC Memory Card is one of the most popular memory card styles used today by camera manufacturers..
4GB: 6MP=1905 images; 8MP 1270 images; 10MP 802 images or 12MP 677 images
8GB: 6MP=3812 images; 8MP 2540 images; 10MP 1604 images or 12MP 1354 images
Note: all memory cards have a DCIM folder (Digital Camera Image) which should never be removed..