Hi Wilfried,
Many thanks for the suggestion - which is about what I do. I have to say that until recently, I only used 2 icons for the application (e.g. the minimise icon, and also the application icon which is larger). (I also use the standard icons with %si). Elsewhere I have used bitmaps (BMP) where it serves the purpose of an icon, i.e. as 'decoration'.
The problem with a BMP bitmap is that it must be rectangular, and what I wanted wasn't. I started by drawing them on a grey background, and this merged in with the grey background that Clearwin gave me. However, the grey is different in various user themes, and even different between the various Windows versions, XP, Vista and 7. At the time, I was using v 4.90 which doesn't support the %gi format code (I'm now on 6.10) and so I investigated icons to use with %ic. They are only 'decorations' on some of my windows.
I drew all of my 15 new icons using IcoFX freeware program, basically by importing the BMP files and then making the grey areas transparent. All of them (and the two original icons) are single images, fixed in size. I have them listed in my .RC file (4.90 didn't support some things in a RESOURCES section and so I compiled the resources separately).
Most of us, me included, aren't real artists, especially down at 16x16 pixels or even 32x32. I therefore look on the web for things that I could use, although I never do an outright copy, simply note the design features and produce my own version. I have a popup help window that explains what every mouse click does. For 'artistic' reasons, it has a picture of a mouse. At the moment I do it with a BMP with a white background, and that works OK because the help info also has a white background. Anyway, I found an excellent mouse icon with transparency, drop shadow effect etc etc - but it there as 5 versions of it from 128x128 down to 32x32 pixels. When I tried it in my code I got the first (biggest) one. Hence my original question.
If I decide to use just one of the icon sizes, I can chop it out of the icon file and put it somewhere on its own with IcoFX. My question was about this case of multiple resolutions with just one ICO file. I had an idea that I might get all my icons in one ICO file!
Regards
Eddie