Denis!
What I want to tell you is not to use run-time image processing at all. IMHO it's hard and useless.
Using those 2 ways of semi-transparency you can just mix color of your picture with background. For example if your picture is grey then it will be grey-blue on blue background and grey-red on red beckground and so on.
Currently I cannot understand what's is your problem. If you just want to prevent image mixing with back color (which makes image unreadible when backcolor is same as image color) then you need to make contours on image of another color. IMHO shadow or bevel effects produce nice borders to make image readible on any background.
AWIcons is my favorite icon tool. It's free for x-USSR users.
http://www.awicons.com/awicons.htmlEverything is ok with that editor but its stupid UI.... Ahhh, I cannot understand why don't thay use normal Windows UI.
/A new technology turns into completely outdated stuff before you have a time to read "Getting Started..." section.
/If there are some "system programmers" then others are unsystematic.