What this implies is that the images within the URL have not been optimized to their fullest potential.
Why is this important?
Optimizing images has been a key part of enhancing website performance for many years. Considering nearly every website incorporates images, the optimization of these graphics is often an overlooked yet significant opportunity for speeding up load times.
By optimizing images, it's possible to reduce the file sizes (measured in KiB) while maintaining a visual quality indistinguishable to viewers, thus accelerating the loading process.
What does the Optimization check?
This Optimization will be activated for any internal URL containing JPEG or BMP images that could potentially be compressed by a minimum of 4KiB.
Loud Interactive gathers all the JPEG or BMP images from a page, adjusts the compression to a quality level of 85, then compares the original and compressed versions. Any image that shows a minimum savings of 4KiB is flagged as capable of being optimized.
How do you resolve this issue?
Optimizing images may seem simple, but the method you choose can vary greatly.
There are typically two phases to the optimization process:
Address the problems with current uncompressed images on the site
Establish a system that compresses images before they are uploaded to the site
For smaller sites, this task can often be taken care of using simple online compression tools like TinyJPG or ImageOptim. Start by compressing the largest files and move to the smaller ones. In terms of ongoing processes, the goal should be to educate the content teams to integrate image compression into their daily content management practices.
For more expansive websites, a hands-on approach may not be ideal, and it may be necessary to look for a more automated, scalable solution in coordination with your development team.
Possible solutions could include:
Implementing image CDNs for automatic optimization
Utilizing a compression plugin or tool
Incorporating an optimization module tailored to your site infrastructure
Further Reading
Efficiently encode images (refer to Lighthouse documentation)
Comprehensive Guide on Image Optimization for the Web
Tips and Tricks for Image Optimization in the Modern Web Era