To fade an image into another or into the background

Select the image

Choose Commands > Creative > Fade Image

Choose a fade style: left edge, right edge, top edge, etc

Click and drag the black square to adjust the fade; you can move it in, out, up and down.
To edit the fade when the image is no longer selected, click on the little pen icon in the layers panel.

Using a mask to fade an image into the background

Place the image on top of the image or background you want to fade into.
Select the Rectangle tool and draw a rectangle to cover the image totally.
With the rectangle selected, click the arrow for the Fill Category drop-down list and choose Radial.
Click in the fill colour box and in the Gradient editor, click the preset arrow and choose White, Black.
In the Layers panel you'll see the rectangle is dark blue because it's selected. Hold your Shift key and then click on Bitmap. This selects both the rectangle and the image.


From the menus, choose Modify >Mask >Group As Mask.
The image now has a mask.  Where you have white you will see the image. Where there is grey it begins to fade, black is totally faded (invisible).

To change the gradient to adjust the fade, click on the pen icon you see in the Layers panel (in the black image which is the mask).
Drag the black box until you are happy with your final image.