It is not possible to insert a shadow behind the image. Depending on the type of shadow, you may get the results that you are looking for by inserting a solid box behind the image and offset it from the image.
To overlap an image over a box:
- Launch the program.
- Open the project you wish to work with.
- Go to the Insert menu and select the Graphic option.
- Browse to the location of the image and insert it.
- Go to the Insert menu and select the Shape option.
- On the Insert Shape window, select the Box option and click the OK button.
- Re-size the shape to match the dimensions of the image from step 4.
- Move the shape to where it is slightly offset from the image.
- Go to the Arrange menu and select the Send Backward option.