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
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.