Mozilla announced Wednesday that it’s working on a new project called mozjpeg that will improve JPEG compression without breaking browsers. The non-profit says it’s doing this because the modern Web uses pictures more than ever before and this can really slow down a page’s loading time. With new compression techniques, they can decrease the time it takes Firefox to load a page full of images.

Even though its building mozjpeg, Mozilla doesn’t see JPEG remaining the dominant image format on the Web. Of course, moving to a new image format brings with its own unique challenges so mozjpeg is being built to help improve JPEG encoding even while the Web moves to a new format.

Production JPEG encoders have largely been stagnant in terms of compression efficiency, so replacing JPEG with something better has been a frequent topic of discussion. The major downside to moving away from JPEG is that it would require going through a multi-year period of relatively poor compatibility with the world’s deployed software. We (at Mozilla) don’t doubt that algorithmic improvements will make this worthwhile at some point, possibly soon. Even after a transition begins in earnest though, JPEG will continue to be used widely.

Given this situation, we wondered if JPEG encoders have really reached their full compression potential after 20+ years. We talked to a number of engineers, and concluded that the answer is “no,” even within the constraints of strong compatibility requirements. With feedback on promising avenues for exploration in hand, we started the ‘mozjpeg’ project.

If you want to try out mozjpeg for yourself, Mozilla released version 1.0 today. It’s a fork of libjpeg-turbo with “jpgcruch” functionality added for good measure. They found this combination can reduce jpeg file sizes by 10 percent and they’re obviously hoping they can increase this with help from the community.