How Retailers Can Fight Against Slowing E-Commerce Sites

This slowness, however, has more to do with poor implementation than with RWD itself. Many web design and usability professionals advocate for practices such as using the largest possible images in their responsive designs and then letting the browser do all the work of scaling them down to the appropriate size. This practice might make the designer's job easier, but it has a huge negative impact on performance.

Oversized, Badly Formatted, Unoptimized Images
We're so accustomed to seeing high-quality images everywhere on the web that we take them for granted and don't think about their heavy performance impact. Page size has a direct impact on page speed, and images comprise at least half a typical page's weight. This represents an extremely fertile ground for optimization.

Most of the websites tested failed to properly implement image optimization techniques that could make their pages significantly faster. Almost half (43 percent) of the websites failed to implement image compression, a performance technique that minimizes the size (in bytes) of a graphic's file without degrading the quality of the image. Progressive image rendering is another technique that can improve both real and perceived performance, yet two out of three websites in this study didn't use progressive JPEGs.

Takeaway: 3-Second Load Times Are Possible
Even for top retailers, tackling web performance is like aiming at a constantly moving target. As soon as you've gotten a bead on one performance issue, a brand new challenge pops up. The silver lining here is that the impact of all this complexity can be mitigated with a thoughtful optimization strategy and a commitment to evolving this strategy to continue to meet future demands.

Overall, there are a number of optimization techniques that site owners can implement to speed up their pages. Here are a few: