Hello,
Images you get after demo content import can neither be used on a live site nor redistributed. If you want to locate the image sources to buy the license, use image search engine https://www.tineye.com/. Height & Width you can change in Theme Options > Header builder > Newsletter – http://prntscr.com/rk2fbu , on the demo – http://prntscr.com/rk2fu9 https://xstore.8theme.com/wp-content/uploads/2018/08/newsletters-popup.png?id=4700 493×229
Regards
