what image size & resolution do I use for slideshows?
The image size depends on the device that will be displaying the slide show. If the device can display 1200x800, then your photos should be 1200x800.
The resolution is irrelevant in this case.
72 is sufficient for viewing on computer screens or TV monitors. Use 150 for viewing on iPad or Mac Book Pro with retina display which allows for zooming.
Retrieving data ...