Essential Image Optimization is an free and online eBook by Addy Osmani:
Images take up massive amounts of internet bandwidth because they often have large file sizes. According to the HTTP Archive, 60% of the data transferred to fetch a web page is images composed of JPEGs, PNGs and GIFs. As of July 2017, images accounted for 1.7MB of the content loaded for the 3.0MB average site.
Per Tammy Everts, adding images to a page or making existing images larger have been proven to increase conversion rates. It’s unlikely that images will go away and so investing in an efficient compression strategy to minimize bloat becomes important.
Essentially Addy pushes forward two key factors:
- We should all be automating our image compression
- Everyone should be compressing their images efficiently