The Gradient Feather Tool (Keyboard shortcut: Shift + G) in InDesign allows for an image to fade from opaque to transparent along a line controlled by the user. With an image selected, drag the cursor from the part of the image that is to be opaque to the part of the image that is to be transparent. Redoing this action will simply replace any gradient feather already in place. With an image selected, double clicking the “fx” icon in the Effects panel will open up the settings for the gradient feather which can be changed. Dragging this same “fx” icon to the trash can will delete the effect.