Poor image optimization on web pages has a clear measurable impact on the user experience, according to a new report entitled Progressive Image Rendering: Good or Evil? published by Radware.
Radware commissioned NeuroStrata, a leader in neuroscientific research, to test three different image renderings. Using facial analysis software, moment-by-moment emotional responses in universal facial expressions of over 250 participants were captured as they were presented with three randomly selected image formats on a web page and were asked to complete tasks that relied on either textual or visual cues. Test subjects were also surveyed about their attitudes and expectations with regard to online images.
Key findings include:
- Default image formats, used by up to 95% of all websites, do not deliver the highest level of user satisfaction.
- 65% of participants have felt frustrated by images taking too long to load.
- 51% of participants wait for most or all of a page’s images to load before they begin to interact with the page.
- 50% of participants feel that the way in which images load has an effect on their web browsing experience.
Typical web pages generally use two of the three image formats used in the study – a standard lossless GIF file and progressive JPEG. The third image file used was a newly developed file, using a proprietary rendering format not yet available to the public. In the report, this new rendering technique was clearly favored by those who were tested compared to the two typical formats.
“Humans are extremely visual. Imagery grabs our attention, evokes a response and sustains our emotional engagement,” says Tammy Everts, performance evangelist for Radware. “As images comprise over 50% of the weight for a typical web page, this neuroscientific study shows that serving images faster on your website does have a direct and measurable impact on the user experience.”
“As we live in a visual age, the speed with which images load on a website tends to be an important issue,” says Dr. David Lewis-Hodgson, chairman of Mindlab International. “Research suggests that a consumer may experience mental fatigue when presented with a relentless flow of complex information on a website. When images are presented in a two-stage process – a method found in Progressive JPEGs – the brain has to work slightly harder to make sense of what is being displayed and in turn, increases frustration levels of the viewer.”