First show the image tool by selecting View in the menubar and then clicking on Image. The check box in front of Image will then be activated. This will show up the picture section on the right hand side of the Parley screen
To add an image to a word make sure the word is highlighted. In the image section on the right hand side click on the Folder icon and choose the picture you wish to associate. On selecting an image for a pair of translations, the bottom right corners of the cells of both the words would be marked with a blue flag. Hovering over this flag with the mouse cursor shows the name and path of the image file.