Had a good discussion with an e-learning developer this week. He had a particular slide layout that he'd used for several slides in his course. On one of those slides, he wanted to add some explorable hotspots, so that his learners could hover over and click on key areas of the slide to reveal more information. He had tried using an Engage Labeled Graphic for this (he took a screenshot of his slide and used that as the image in his Labeled Graphic), and this came pretty close to what he was looking for. But when he inserted the interaction into Presenter, he didn't really like how the interaction frame made the slide look different from the other slides in his course.
So here's the solution I shared with him.
Rather than using an image of his slide for the Labeled Graphic, he instead used a tiny 1x1-pixel image. This image is so small that it ends up being virtually invisible in the published interaction. This way, he was able to allow his PowerPoint slide master to show right through on the interaction's placeholder slide. The end result is that the slide looks super-seamless with the rest of the course, as if the Labeled Graphic markers had been placed directly on the course slide itself.
The following tutorials show a walk-through of how to achieve this effect. It involves using a simple grid to help with the placement of the Labeled Graphic markers within Engage, and then swapping out that grid with the 1x1-pixel image. Both the grid and the 1x1-pixel image are available in the Downloads section.