Setting WPF image source in code

After having the same problem as you and doing some reading, I discovered the solution - Pack URIs.

I did the following in code:

Image finalImage = new Image();
finalImage.Width = 80;
...
BitmapImage logo = new BitmapImage();
logo.BeginInit();
logo.UriSource = new Uri("pack://application:,,,/AssemblyName;component/Resources/logo.png");
logo.EndInit();
...
finalImage.Source = logo;

Or shorter, by using another BitmapImage constructor:

finalImage.Source = new BitmapImage(
    new Uri("pack://application:,,,/AssemblyName;component/Resources/logo.png"));

The URI is broken out into parts:

• Authority: application:///

• Path: The name of a resource file that is compiled into a referenced assembly. The path must conform to the following format: AssemblyShortName[;Version][;PublicKey];component/Path

  • AssemblyShortName: the short name for the referenced assembly.
  • ;Version [optional]: the version of the referenced assembly that contains the resource file. This is used when two or more referenced assemblies with the same short name are loaded.
  • ;PublicKey [optional]: the public key that was used to sign the referenced assembly. This is used when two or more referenced assemblies with the same short name are loaded.
  • ;component: specifies that the assembly being referred to is referenced from the local assembly.
  • /Path: the name of the resource file, including its path, relative to the root of the referenced assembly's project folder.

The three slashes after application: have to be replaced with commas:

Note: The authority component of a pack URI is an embedded URI that points to a package and must conform to RFC 2396. Additionally, the "/" character must be replaced with the "," character, and reserved characters such as "%" and "?" must be escaped. See the OPC for details.

And of course, make sure you set the build action on your image to Resource.

var uriSource = new Uri(@"/WpfApplication1;component/Images/Untitled.png", UriKind.Relative);
foo.Source = new BitmapImage(uriSource);

This will load a image called "Untitled.png" in a folder called "Images" with its "Build Action" set to "Resource" in an assembly called "WpfApplication1".

This is a bit less code and can be done in a single line.

string packUri = "pack://application:,,,/AssemblyName;component/Images/icon.png";
_image.Source = new ImageSourceConverter().ConvertFromString(packUri) as ImageSource;