Not sure how the presenters feel about this, but if possible after (or before if possible) the presentation a decent resolution version of the original and final image was provided so that we could attempt some of the things we say in the presentation on the image. I don't see why any of the viewers would not be for this, but I know that the presenters may not be comfortable with this (which I would understand). However for those that don't mind it would be awesome to have such files. PSD would be even more awesome though decent sized jpegs of before and after would be great.
I would propose that the download be available only under the agreement that it is for personal education purposes and that the original nor modified versions of the original are allowed to be shared online or otherwise.
I understand that this may not be acceptable as per some model/agency agreements, or that the presenter might not want to put any of their work out there like that, but I do think it would be really helpful (even if its just a higher res version of the final). Its just hard to appreciate some things on the lo fi screen presenter.