inddPreview comes with a Quick Look plug-in on board, that enables Finder to show preview images of InDesign® documents* without the need to open them with InDesign®.
The app itself is primarily a medium to provide the Quick Look plug-in. In addition you can use the app to copy those preview images to the clipboard to use them elsewhere.
Works with InDesign® documents (.indd), InDesign® template files (.indt), InDesign® snippets (.idms) and InCopy® documents (.icml) from CS2 to CC2018.
*InDesign® can embed preview images when saving the document. How many and of what size/quality they are can be configured in the preferences of InDesign®.