1.Open you picture image
2.Draw a box the same colour as you want the layer, (colour to fade into the picture).
3.Ensure that the coloured box is the top layer.
4.Click the box and press F8 to create a graphic.
5 Click on Command > Creative > Fade Image.
6.Choose the direction of the fade and press ok.
You can move the fade by clicking on the faded box and then dragging the command line in the direction you want it to add or subtract the fade..
Is that what you meant??