Is GNU Free Documentation License photos/videos get approved by themeforest if you use theme in your themes ?
like the one wikimedia provideshttp://en.wikipedia.org/wiki/GNU_Free_Documentation_License http://commons.wikimedia.org/wiki/Main_Page
You can read ‘Commercial Redistribution’ section at the license page http://en.wikipedia.org/wiki/GNU_Free_Documentation_License
For me, it is always safe to use image placeholders at your main files (PSD/Template). And you can use any images for your Live Preview (as long as you have rights to use it). It is general rule here…