A transparent color replaces one color in an image and lets the background of the page show through the image where that color was. An image can have only one transparent color. If an image already has a transparent color, selecting a new transparent color returns the existing transparent color to its original color.
You can make a color transparent in an image using the Make Transparent button. This changes the pointer to the Make Transparent pointer. Click a color to make it transparent.
If an image is a JPEG image, the FrontPage Editor prompts you to convert the image to GIF format when you make a color transparent. Transparency is not supported in JPEG images.