Click in the
Advanced property to display the Image Preview window.
Mouse over the pixels in the image to display their RGB values.
Click the eyedropper and select a pixel in the image that is the
color you want to become transparent.You can use the zoom slider to
resize the image and you can drag to pan the image within the
window.The color you selected appears in the drop-down next to the
eyedropper icon. You can add multiple transparent colors by repeating this
process, and remove colors by clicking Delete Selected Color or Delete All
Colors icons. The image window previews the image with the transparency you
selected.
in the
Advanced property to display the Image Preview window.
and select a pixel in the image that is the
color you want to become transparent.