How to save an EXIF format image file in .NET 3.5

Question

I want to save an image in EXIF format using System.Drawing.Image.Save or a similar method in a C# application using .NET framework v3.5. The MSDN documentation lists EXIF as an option for ImageFormat. However, it does not seem to be supported - at least not without some configuration unknown to me. When I enumerate the built-in encoders via ImageCodecInfo.GetImageEncoders() EXIF is not included. (Built in encoders on my machine (Vista Ultimate x64) are: BMP, JPEG, GIF, TIFF, and PNG.) If I save an image using the ImageFormat.Exif property, I simply get the default PNG format.

How can I save an image in EXIF format using .NET 3.5?

Answer 1

Not an answer, just a reflection: To me, EXIF means the meta data you access via .PropertyItems on a bitmap. So, I'm used to store and retrieve EXIF data in JPG files, I've never heard of an EXIF image format...

Answer 2

Have you seen this: Lossless JPEG Rewrites in C#

Answer 3

EXIF isn't a image file format per se, but a format for meta-data found within JPEG images conforming to the DSC (Digital Still Camera) standard as specified by JEITA.

GDI+ (i.e. Microsoft .NET Framework) allows you to read/write metadata image properties via the Image.PropertyItems, however the EXIF properties exposed by GDI+ are pretty cumbersome and don't convert the values the way you would expect. A lot of work is actually needed to be able to natively read/write these values (e.g. you'd need to unpack binary fields containing specially encoded values according to the JEITA spec).

A straight-forward open-source library which implements all the standard EXIF properties can be found at http://code.google.com/p/exif-utils/ This is probably the easiest way to do this. See the simple included demo which reads in a file, prints out all the EXIF properties and then adds a property to the image.