This is more of a general question. As everyone is aware it's possible to store 1 or more icons within the resource section of a PE file.

If the file is an EXE, then WindowsNT will use the first icon listed as the application icon within the group_icon structure. (Win9x will using the first in alphabetical order, but for my purpose lets even forget that Win9x existed).

Now say, within the resource section I have multiple icons, all with the same name but at different resolutions, will Windows choose the matching size/resolution for display in explorer ,eg when you switch between icon, detail, thumbnail view, etc does it select the 32x32 icon instead of the first icon, or does it scale the first icon to fit (eg 128x128 down to 32x32)?

If it scales, does someone have any good resources on creating good icons that scale well (when used with scaling algorithm that Windows use).

Now fast forward to Vista... I haven't been able to find any solid references on how Vista handles these icons (and since I don't have Vista installed, I can't test it personally).

Since Vista is apparently "DPI-aware", does it do things differently? I've read Vista can use PNG encoded icons up-to 256x256, which may be of interest.

PS. All my icons are 256x256 native, and then resized using Paint.NET, and then converted to *.ico's...

I think since Windows 95 it handles multi-resolutions icons, for each thing to do.
http://board.flatassembler.net/topic.php?t=6817 - Here's example.

Thanks, I've sorted out the multi-resolution issue with the icons.

Windows will only use the first icon, however if that icon is a "multi-icon file" it'll select the correct resolution from within the icon file...