Yes, I can slow down the slide frequency. This Sony basically has computer like features that let you do a lot of different things. I'm using a USB thumb drive, but it is capable of wirelessly streaming photos from a pc over a home network. I tried it and it actually works great, but the thumb drive is easier for me and does what I need it to do.
Not sure if I'm going to put a frame around it. It looks great as as (very clean) so probably not. I've put in some posters with different aspect ratios like half sheets, inserts, six sheets and three sheets, and a frame wouldn't look right (I don't think) when those images are displayed.
The posters that look best are the 3 sheets as they naturally take up most of the screen space due to their aspect ratio.