Users expect websites to download quickly, and if they don't, the users get frustrated and leave the site. The amount of time the average user is willing to wait before leaving the site is known as the threshold of frustration. Research sets the threshold at ten seconds. That is, if the page does not download in ten seconds, the visitors are likely to leave.
Web designers should pay special attention to anything that increases download time. The main culprits are large images. Image files increase download time, hence you should try to limit the number of images and size of images on a page.
Alex Calvert WMU School of Communication, Kalamazoo Michigan
June 21, 2016