Thumbnails in Powerpoint and Word

I do a lot of research of competitor websites that involves taking screenshots. I use SnagIt for the screen captures and that works great. But what I’m struggling with is insert a thumbnail of the screenshot in MSPWPT or MSWORD that when clicked will open in full view. Once the image is viewed I would like to close it and have the ppt or doc file revert to the original thumbnail. I’ve tried the insert/object path but get stuck at the change the icon setting. If I could get the icon to display my thumbnail that solution would be fine. Other suggestions welcome.