Nice images, though the transparent black "bar" across each one on the bottom was bothering. Maybe a positioning bug???
As for your question, if you look below:
static var enablePlayButton:Boolean = false; //Whether to show play button for autoplay mode.
static var playAtStart:Boolean = false; //Whether to automatically start playing. <CHANGE TO TRUE
static var displayTime:Number = 5; //Number of seconds each image will display in autoplay mode.
and change the line variable/Boolean from false (the default) to true, it should work. Then just republish the source fla. and you'll be fine. BTW, this is changed in the "Option.as" file typically found here (if you unzipped the simpleviewer pro file into its own folder):
SimpleViewer Pro\SimpleViewer v1.9 Pro\source\com\airtightinteractive\apps\viewers\simpleViewer
Also be sure to publish your .fla with the right name and in a location you can find it, so it will not overwrite the original included in simpleviewer pro.
Hope that helps.