When I double click on a .ico file in Visual Studio 2010 (Professional), it opens what looks like an icon editor. It looks like it should be really easy to pick a color from th
I finally found an easy way to do it without visual studio, GIMP https://www.gimp.org/downloads/
For the PNG images used as button icons that Visual Studio cannot edit you can use external editor as MS Paint.
The icon is built by an external app.
For Visual Studio 2008 & 2010 image editor,
"Using the Image Editor, you can view 32-bit images, but you cannot edit them."
http://msdn.microsoft.com/en-us/library/s1dadd79.aspx
If you have a Mac OS X machine around, you can edit Windows icons with the Icon Composer application included with the free Developer Tools.
I just discovered this accidentally while working on some cross-platform Mac/Windows code.
You can't directly edit 32-bit color icons but you can convert them manually to 24-bit :
Right click > Add new icon
Open your Icon1.ico
file.
Right click > New Image Type
or press Ins
to open the New Icon Image Type
dialog.
Select the format you want, say 96x96, 24 bit
or add any custom size and color depth.
Then copy/paste from your 32-bit icon file and save.
Et voilà ! You can now edit your 24-bit color icon.
Doh! I needed to enable View -> Toolbars -> Image Editor.
Thanks to @detale.