First, remember that Premiere Elements is a VIDEO editing program. So your results are going to be video resolution: essentially 640x480 pixels. So if you're not planning to show your slideshow on a TV and you're looking for a program to create a slideshow you can watch on your computer at full resolution, this is not the program for you. (ProShow Gold would be a better choice.)
But if you're looking to create a video from your still photos:
1) Ensure all of your photos are no larger than 1000x750 pixels in size.
2) Be sure to render your timeline (press Enter) whenever you see red lines above photos or any new clips you add to your timeline.
3) For the BEST quality video from your slides, right click on each still photo on your timeline and select Field Options/Flicker Removal.
Welcome to the forum.
How do you plan on delivering your SlideShow?
That can have a major impact on exactly how you create the SlideShow, and what Project Preset you choose in PrE, then exactly the dimensions, that you Scale your Images to.
Will you have any Video, or will everything be Still Images only?
For many types of SlideShows, I will second Steve's rec. for Pro Show Gold, or their Producer.
Thanks for your prompt reply. I'vecheck out the things you mention but no improvement. I'll look at Pro Show Gold as you suggest.
Geoff Walter (marmaladelover)
Steve, have you found a way to apply flicker removal as a default or to multiple clips at once? Paste Attributes doesn't do it, and you can't apply to a group. I can have quite a few stills in a slide show and obviously time consuming to apply individually.