Most media players will pause if you hit the space bar, you also have the player controls of course.

Quote Most media players will pause if you hit the space bar, you also have the player controls of course.

I was not clear. I know how to stop a slide once shown. What I want to do is show a slide manually and not worry about it automatically without any action on my part going to the next slide. I want a slide to stay on the screen until I manually select the next slide. It seems all slides in PD15 must have a duration assigned and then they proceed to pop on the screen automatically according to that duration.

Perhaps Power Directro is not suited for your need. Do you have Power Point or even PhotoDirector? .
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BoilerPlate: To posters who ask for help -- it is nice to thank the volunteers who try to answer your questions !
Anything I post unless stated with a reference is my personal opinion.

The only option that is available to you (that I know of) is to define the default duration of images in your settings. You can of course change the duration of each one individually once placed in the timeline. Being able produce a video to which you can reliably time your presentation is virtually impossible though in my experience.

I think you need to consider something like a wireless presenter to give you manual control and for any sort of serious lecture/presentation use I would suggest you'd be better off using MS Powerpoint or similar especially if you're just working with still images.