1. Insert a rectangle the size of a slide in the PPT and a rounded rectangle with a "widescreen" shape.
2. Use the image tool "Merge Shapes" to "split" the rectangle and rounded rectangle to make a "window". Set the fill color of the large rectangle with a rounded rectangular window in the middle to black.
3. Re-insert a rounded rectangle that is as large as the window, set the fill color of the rounded rectangle to no fill, the border to be thick, and set a three-dimensional effect.
4. Insert the picture material to be played and place it in the "horizontal center" position.
5. Add "fade in" and "straight (up)" (path) animation to the picture material.
6. Bring the picture to the back. Play the slideshow, you can watch the effect of the picture slowly moving up through the window.