Multicolored images present more problems. If you can't provide a monochrome version, you can try creating one on the fly by identifying light and dark areas as foreground and background. For example, a bitmap that has a multicolored object on a white background can be mapped with all colors other than white in the appropriate system foreground color and with white in the system background color. These colors can be reversed for images designed with a dark background. Draw text on a plain, contrasting background to make it much easier to read.
Text is most legible when drawn against a plain background of a contrasting color.
Text drawn over a varied background, such as a wash of colors, a bitmap image, or lines, may be illegible for many users because the image can distract from or blend with the edges of letters making them hard to recognize. This is especially true when the screen is magnified, or viewed with altered colors. If you use such backgrounds, you should provide an option to omit the image and revert to a plain background. Omit the background in response to the High Contrast option, which is discussed below. Omit the background if the foreground color changes or consists of mixed colors.