I don't want to put XML comments or anything in source code.
I want to do something like this:
- Click add class - type name
- Click add method - type name
- Add description, images, etc.
You can do that, you know the XML comments in C# are supported by the compiler, the output is this XML and it's just XML.
You could build a simple tool for that, using reflection. It's a good exercise to learn more about reflection and the .NET type system.
Though, I would actually advice against it because having the source code and documentation in one place makes it easier to adhere to the DRY principle. You don't want your documentation and source code drifting apart and you can always collapse the comments (that way, they don't show up when your editing the source code). And you documentation will then be under source control as well.
Sandcastle makes nice msdn like help files from xml code.
Update
I am sorry for my missleading answer. You can try Adobe Robocop. We used it to make high quality chm files even with animated gif.