How can I find out when a picture was actually taken in C# running on Vista?

Image myImage = Image.FromFile(@"C:\temp\IMG_0325.JPG");
PropertyItem propItem = myImage.GetPropertyItem(306);
DateTime dtaken;

//Convert date taken metadata to a DateTime object
string sdate = Encoding.UTF8.GetString(propItem.Value).Trim();
string secondhalf = sdate.Substring(sdate.IndexOf(" "), (sdate.Length - sdate.IndexOf(" ")));
string firsthalf = sdate.Substring(0, 10);
firsthalf = firsthalf.Replace(":", "-");
sdate = firsthalf + secondhalf;
dtaken = DateTime.Parse(sdate);

I maintained a simple open-source library since 2002 for extracting metadata from image/video files.

// Read all metadata from the image
var directories = ImageMetadataReader.ReadMetadata(stream);

// Find the so-called Exif "SubIFD" (which may be null)
var subIfdDirectory = directories.OfType<ExifSubIfdDirectory>().FirstOrDefault();

// Read the DateTime tag value
var dateTime = subIfdDirectory?.GetDateTime(ExifDirectoryBase.TagDateTimeOriginal);

In my benchmarks, this code runs over 12 times faster than Image.GetPropertyItem, and around 17 times faster than the WPF JpegBitmapDecoder/BitmapMetadata API.

There's a tonne of extra information available from the library such as camera settings (F-stop, ISO, shutter speed, flash mode, focal length, ...), image properties (dimensions, pixel configurations) and other things such as GPS positions, keywords, copyright info, etc.

If you're only interested in the metadata, then using this library is very fast as it doesn't decode the image (i.e. bitmap). You can scan thousands of images in a few seconds if you have fast enough storage.

ImageMetadataReader understands many files types (JPEG, PNG, GIF, BMP, TIFF, PCX, WebP, ICO, ...). If you know that you're dealing with JPEG, and you only want Exif data, then you can make the process even faster with the following:

var directories = JpegMetadataReader.ReadMetadata(stream, new[] { new ExifReader() });

The metadata-extractor library is available via NuGet and the code's on GitHub. Thanks to all the amazing contributors who have improved the library and submitted test images over the years.

With WPF and C# you can get the Date Taken property using the BitmapMetadata class:

MSDN - BitmapMetada

WPF and BitmapMetadata

In windows XP "FileInfo.LastWriteTime" will return the date a picture is taken - regardless of how many times the file is moved around in the filesystem.

I have great doubts XP was actually doing that. More likely the tool you used to copy the image from the camera to you hard disk was reseting the File Modified Date to the image's Date Taken.

you'll have to check the EXIF information from the picture. I don't think with regular .Net functions you'll know when the picture was taken.

It might get a little complicated...

There will be EXIF data embedded in the image. There are a ton of examples on the web if you search for EXIF and C#.