A very quick hack to check if an image is a photo in C#, using image properties, is to see if there’s a “camera manufacturer” property set:

foreach (var img in Directory.GetFiles(imagedump))
{
    using (var fs = new FileStream(img, FileMode.Open))
    using (var i = Image.FromStream(fs))
    {
        foreach (var p in 
            from p in i.PropertyItems
            where p.Id == 271 // manufacturer property
            select p)
        {
            var encoding = new ASCIIEncoding();
            var manufacturer = encoding.GetString(p.Value);
            Console.WriteLine("Camera make:{0}", manufacturer);
        }
    }
}

Learned from a little msdn article; the value 271 is the integer version of the hex “0x010F” in the table of common IDs.