Q:
Can I upload an entire powerpoint presentation ?
A:
The best way of creating a slideshow is to design it in powerpoint or keynote and then 'Export' all the slides as image files e.g. png files. You can then upload each slide to the slideshow and either name them 1,2,3 etc or provide description names e.g. Introduction, Background etc
Q:
Can the slideshow fit the entire screen ?
A:
The slideshow is designed to be prominent on all screen formats, and to maintain it's aspect ratio to provide the best display for your slideshow designs.
At present there is not an option to stretch the slideshow to fill the screen.