I have a project that was using Presentation and Slide to process .ppt files. One part of the code uses the GetThumbnail() overload that takes an ICollection to get a thumbnail of just one element or of a group of elements. This overload actually stopped working correctly sometime after version 5.0, including other overlapping elements in the snapshot, so we stayed on 5.0 for a long time. I've just confirmed it still does that in 7.0.
Now we're going to start processing .pptx files using PresentationEx, SlideEx and so on. But SlideEx does not have the overload I want in GetThumbnail(). Is there another way to get a snapshot of a single element or a collection of elements, rather than the entire slide?