I am a beginner with Paint.net but am not using it for anything advanced just need some custom map symbols. I am downloading some simple 256X256 .png files that I then reduce to 16X16 and save as .bmp 24 bit. The original .png files have what I would call a "transparent" background. Looks like a checkerboard gray and white pattern. But when the .png file is used as is, the only thing that shows is the symbol itself. In other words if the symbol was a black X and was inserted on the map only the X would show, no opaque background. This is what I need. But after reducing the size to 16X16 and saving as .bmp 24 bit, and then using the file, the background has changed to solid white which of course makes a white square on the map. Why is this happening and how can I keep the original transparent background that is in the downloaded .png file? Thanks.
I have read other threads, including one just below this one, that sort of ask similar questions. But what they are doing is much more complicated than what I want and don't directly state how to preserve the transparent background of the original .png. I have read other places that to make a pixel transparent, set its color to magenta (RGB = 255, 0, 255), but I don't see how to do that or understand if it would even work.
