Changing the transparent colors in an image is useful for making it mesh well with a website background, for layering multiple images on top of each other, for better showing any text that is layered on top of an image, for removing or hiding part of a picture for emphasis, etc. But understanding how to change the transparency is not so easy. Transparent image parts get the same color as the paper on which they are printed. If we talk about the web page, then the color is the same as the electronic display background. Image formats that support transparency include GIF, PNG, BMP, TGA, and TIFF. For practical application purposes, out of this list only PNG and GIF images natively support transparency. Bitmap (BMP) files do not inherently support transparency and only some software programs can read an alpha layer (the transparency layer) on a bitmap file. And PNG is probably the most popular image format used mostly for its transparency support. ImageConverter Plus supports transparency for the following output image formats: TGA, and PNG. You cannot make more than one color in a picture transparent. Areas that seem to be a single color may be comprised of a variety of different color variations mixed up. The color you select may appear in only a small area. That is why transparent effect is not so obvious.