Image optimisation increases site revenue: claim

The two organisations took up the hypothesis "Would the optimisation of image display improve page load times enough to boost session lengths, ad impressions and revenue?" in order to test it.

They found that a 9.6% increase in page-load times led to a 2% increase in time spent on the site. For mobile users, a 34% improvement in page-load times led to users spending 13% more time on a site.

Akamai extrapolated this data and calculated that a site which had 100 million unique visitors a month could generate potential additional revenue of £65,000 a month with this increase in page views.

{loadposition sam08}The potential increase inn revenue was larger for mobile publishers – £77,000.

Previous research by Akamai found that page-load times had an effect on ecommerce, with findings that Amazon and Walmart suffered a 1% loss in revenue for every 100 milliseconds of delay in the site loading.

It also found that Walmart had increased conversion rates - from a visit to buying something online - by 2% for every second of performance improvement.

The testing was carried out over three months by Soasta, now a part of Akamai but an independent company when it carried out the tests.

"(It) proved the undeniable business value of adjusting images to serve the right one in the right format to each device based on its connectivity at that moment," Akamai and the Telegraph said in a white paper.

"In fact, the study showed that these optimisations (of images) led to an average 50% reduction in image weight, with no change to perceptual quality. This led to a 9.6% reduction in page-load time and a 2% increase in session length on average."

The image optimisation was done through Akamai's Image Manager from 1 September 2016 onwards.

The white paper can be downloaded free after registration.