Take it all off! Lossy Image Optimization

Billy Hoffman (Rigor)
Web Performance Ballroom ABCD
Presentation: external link
Average rating: ****.
(4.11, 9 ratings)

For the majority of websites, images consume the most bandwidth and are the most requested content type. The focus over the last few years has been on lossless image optimization tools, which typically achieve between a 5% to 15% reduction in size. With images constituting such as large percentage of the web, what else can be done to reduce file size while preserving the perceived quality of images?

This is where lossy image optimization comes in. Lossy image optimization allows between 30% to 70% file size reduction by discarding some of the image data. This lossy aspect has caused most people to immediately discount lossy image optimization as a realistic option. However this is short sighted. MP3s achieve enormous size reduction by using knowledge about how we hear and process sound to discard audio data without significant losses in perceived quality. Similarly, by intelligently approaching images and their content, we can apply different image formats and lossy compression schemes to achieve substantially smaller file sizes while maintaining image quality and user experience.

In this presentation, we will discuss different techniques and approaches to further optimize your web images without noticeable quality loss. We will provide guidelines that show when lossy image optimization is appropriate and how to apply it. We will show before and after pictures to illustrate when lossy optimizations succeed and fail, and how much savings can be achieved. We will demonstrate how free tools can be used to automate the detection and optimization of candidate images for lossy compression. Finally we will discuss how new web image formats like WebP and JPEG-XR might change the image optimization landscape.

Photo of Billy Hoffman

Billy Hoffman


Zoompf was founded by Billy Hoffman, a recognized expert in the field of the web and web security. Billy was the lead researcher at web security firm SPI Dynamics and served as the manager for Hewlett-Packard’s Web Security Research Group following Hewlett-Packard’s acquisition of SPI in 2007. Billy’s research has focused on Web 2.0 technology and security threats, automated discovery of web application vulnerabilities, and web crawling technologies. His work has been featured in Wired, Make magazine, Slashdot, G4TechTV, and in various other journals and Web sites. Billy has presented his work internationally and is regular presenter at security conferences including RSA, Black Hat, AJAXWorld, and Shmoocon. Billy is also the author of the book Ajax Security, the definitive guide to web security in a Web 2.0 world, published by Addison Wesley in December 2007.

As Billy conducted web security analysis throughout the globe, he consistently noted that the performance of most websites was suboptimal. He also noted that this lack of optimization resulted in both poor user experiences and lost revenue for website providers. Recognizing an opportunity to apply his extensive web development skills in this exciting new area, Billy founded Zoompf to develop technology and services specifically designed to optimize website performance.

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Picture of Billy Hoffman
Billy Hoffman
06/20/2011 3:14am PDT

Thanks for the great feedback. You can download the presentation slides here: zoompf.com/resources

Picture of H. "Waldo" Grunenwald
H. "Waldo" Grunenwald
06/19/2011 10:35pm PDT

Excellent talk. Great example of a talk by a vendor without being a sales pitch. Talked about the how and why (with solid, actionable guidelines), and then said “I can take make this easy for you.”

Tom Hoppe
06/16/2011 9:41am PDT

Is the presentation available anywhere? I missed this session as I was attending a different one. Thanks!

Picture of Jon West
Jon West
06/15/2011 10:18am PDT

While reducing image size isn’t a new topic for performance pros this is the 1st time I’ve seen recommendations presented so clearly. Great talk which should convince anyone overlooking image optimization to reconsider.

Picture of Steve Souders
Steve Souders
05/19/2011 8:16am PDT

Billy will challenge the belief that lossless is the only way to go. Images make up 60% of all the bytes transferred on the Internet (according to the HTTP Archive). If there’s a way to reduce their size it could be a major improvement to web speed.

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