Windows PNG compressed 256x256 icons are supported in Microsoft Visual Studio 2008+. We've tested PNG compressed icons on Visual C++ 6.0 and Visual .NET 2003/2005 and they all reject the icon during the resource compilation:
Error RC2176: old DIB in res\app.ico; pass it through SDKPAINT
This is unsurprising to us since this new ICO file format introduces a new header which points to raw PNG data. Of course the compiler returns a false error message. The DIB header is not old, it is PNG. Passing it through SDKPAINT does not help.
Windows Vista compressed icons have also been reported as not functioning in the Delphi programming environment. New components will no doubt be developed in the future that identify these shortfalls.
Creating a project using a 256x256 PNG icon with Visual C++ 6.0 and .NET 2005
To follow the procedure below you need Axialis IconWorkshop 6.10 (Tryout Version or Corporate Edition)
Create a 256x256 icon with all formats embedded as recommended for Windows Vista. Save your icon without compressing your 256x256 formats. If your icon already contains PNG compression (like the one we've created in the procedure above), follow this procedure:
1. Open the icon file containing the PNG compressed formats icon in IconWorkshop.
2. On the left side of the document window you see all the formats available. Locate the 256x256 formats which are compressed: A small overlay icon indicating the compression is displayed (). For each of them, do the following step:
3. Right click on the format (in the list if available formats, not in the editor area). A menu opens, choose "PNG Compressed Image Format (Windows Vista)" to remove the compression.
4. Save the icon. Redo the same procedure for all the 256x256 icons of the project.
Create Icons using a Professional Authoring Tool
Once the icon is saved without compression, work on your project as usual. The compiler will handle the icon images correctly since they are not PNG. When your project is finished and before releasing the program file, follow the procedure below:
1. Open the EXE file containing the uncompressed icon in IconWorkshop.
2. The file opens in a document window with all the embedded icons displayed. Be sure to display all the formats in raw: choose "View/Display Icons/All Formats In Raw".
3. Double-click on the icon you want to compress. It opens in another document window.
4. In the list of available formats (vertical list on left), right-click on the first "256x256 RGB/A" format, a menu opens. Choose "PNG Compressed Image Format (Windows Vista)". A small overlay icon indicating the compression is displayed ().
5. Repeat step 4 with the other 256x256 image formats (if any).
6. Save the icon "File/Save". Close the icon window.
7. Back in the EXE document window, you see the compression overlay icon () displayed on all the 256x256 formats. Repeat steps 3 to 6 for all the other icons containing 256x256 images (if any).
8. Save your EXE document, close the window.
9. You're done! The EXE file size is smaller indicating that the compression is made.