A JPS is simply a 3D jpeg. in otherwords it is a jpg with 2 side by side images in it. That's it. nothing special. My cell phone, Optimus 3d and LG thrill 4g make them. I think that the Evo 3d makes MPO files which are the same thing.
for the thumbnail, I suggest that you allow the option to view them as left / right or both and put a little 3D tag on the thumnbnail.
Please add .JPS to the file associations dialog w/thumbnails
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