2010 update: Lo, the Web Performance Advent Calendar hath moved Dec 23 This post is the one-before-last article in the 2009 performance advent calendar experiment. Often performance improvements come with their drawbacks, sometimes improving performance causes pains in other parts of the development process or strips stuff from the final product. Sometimes there’s even a […]

2010 update: Lo, the Web Performance Advent Calendar hath moved Dec 13 This post is part of the 2009 performance advent calendar experiment. Stay tuned for the articles to come. People are often afraid to use PNG because they think that: a/ it doesn’t work in all browsers, or b/ filesizes are bigger than GIF […]

2010 update: Lo, the Web Performance Advent Calendar hath moved Dec 12 This post is part of the 2009 performance advent calendar experiment (12 articles down, 12 more to go). Stay tuned for the articles to come. Let’s continue the topic of reducing file sizes started with the previous post and talk about making images […]

2010 update: Lo, the Web Performance Advent Calendar hath moved Dec 9 This post is part of the 2009 performance advent calendar experiment. Stay tuned for the next articles. One of Yahoo!’s first batch of performance best practices has always been “Avoid duplicate scripts” (check Steve Souders’ post). Later we added “… and styles”. This […]

2010 update: Lo, the Web Performance Advent Calendar hath moved Dec 7 This is the seventh in the series of performance articles as part of my 2009 performance advent calendar experiment. Stay tuned for the next articles. UPDATE: While this post is an interesting study, the problem it solves turns out to be much simpler. […]

2010 update: Lo, the Web Performance Advent Calendar hath moved Dec 5 This is the fifth in the series of performance articles as part of my 2009 performance advent calendar experiment. Stay tuned for the next articles. Let’s talk a but about waterfall optimization – the first thing that happens in Mr.Page’s life. The best […]

2010 update: Lo, the Web Performance Advent Calendar hath moved I like 24ways.org’s idea of a webdev advent calendar – publishing one article per day from Dec 1st to Dec 24. I thought it would be cool to have the same thing on web performance topics. Our young performance community would benefit from a year-end […]

As you know yours truly is a guitar hero wannabe. So I’m playing with the idea of recording a song/video called “Give PiNG a Chance”, cover of “Give peace a chance”. Hopefully whoever hears it will then think twice before saving a GIF instead of PNG. Imagine. And the web will be as one… 😀 […]

A few months ago I gave a 5 minute Ignite talk at the Velocity conference. (My previous post talks about the Ignite experience.) I thought they recorded the video and wanted to share but seems like it’s not happening. So below are the slides from slideshare. The ignite talk rules are: 20 slides that change […]

What can your tired old page, once loaded and used and read, can do for your user? It can preload components needed by the next page, so when the users visit the next page, they have the new scripts, styles and images already in the cache. Next page loads faster and the user’s happy. On […]

This is one of those note-to-self type of posts. Just went through the exercise of installing a number of PNG tools on the Mac and here are some notes. The instructions below should probably work on any unix box. AdvDef, AdvPng, … There is a number of Adv* tools (advdef, advpng, advmng, advzip) packed together […]

UPDATE: It’s very important to have a closing separator in the MHTML document, otherwise there are known issues in IE7 on Vista or Windows 7. The details are here. In the previous post I described what data: URIs are and how they are useful to reduce the number of HTTP requests. Now, the problem with […]

If you follow this blog you already know the infamous website performance rule #1 – reduce the number of HTTP requests. Actually, to celebrate Earth Day and to jump the “go-green” wagon/jargon, my favourite performance mantra as of late is “Reduce, Reuse, Recycle” (the Recycle part is a wee fuzzy but, oh well) So to […]

If you’ve followed the series of image optimization posts on the YUIblog, you’ve probably seen the one about progressive JPEGs. In short, if a photo is over 10K it has a high probability of being smaller in file size when you use progressive JPEG. How do you turn a normal, baseline JPEG into a progressive […]

I know, you don’t have broken images on your site, it’s unprofessional and ugly. But sometimes you may be loading images that you don’t control and you never know what’s going on on the other server you’re expecting to serve, but it may not feel up to the task. One nice and simple strategy to […]

JPEGtran is cool because it lets you optimize JPEG images losslessly by: Stripping meta data (meta is sometimes bulky and useless for web display) Optimizing Huffman tables or Convert a JPEG to progressive encoding From my experience 1 is more important than 2 or 3 and 3 gives better results than 2 for images over […]

Thanks to Joseph Jiang who translated in Chinese parts of my image optimization articles from the YUI blog If you read Chinese, visit http://josephj.com/entry.php?id=209.

… but doesn’t write PNG8 with alpha transparency, unfortunately. This comment on the YUI blog got me all excited by the possibility of having another designers tool other than Fireworks that creates PNG8 (palette PNGs) with alpha transparency. Overall Paint.NET is a very simple and friendly program (as a non-designer I’m often intimidated by Photoshop’s […]

ExifTool looks like a very promising tool to fiddle with all sorts of JPEG metadata (needed for smush.it) but first I had to make sure I can install it on Dreamhost. Although installation didn’t go as described on the exiftool site (since I don’t have sudo access on Dreamhost), it’s still installable and it’s actually […]

I’m currently experimenting with different tools for optimizing PNG images to figure out strengths/weaknesses of each. Only considering free, ideally open-source, tools that can be run from the command line. For smush.it I just picked pngcrush for no particluar reason and I was thinking that once I have the optimization tool up and running and […]

Was having fun today with idiff.php – a PHP shell script to tell you if two images are visually different by comparing them pixel by pixel. If there’s a difference, the script creates a third image – black background with the different pixels in green. Only after writing the script I found that there’s an […]

Thanks to everyone who attended my image optimization talk at the php|works + PyWorks conference in Atlanta. And thanks for all the questions! I love questions, feels more natural – just geeks talking to geeks – as opposed to one guy sitting on a podium and talking. And the slides: Image Optimization for the Web […]

What’s new in smush.it? The old domain smushit.com now redirects to the new one smush.it, which is what we originally intended but the domain registration took a while and we quickly got smushit.com just in time for the Ajax Experience announcement of the tool There’s a bookmarklet version of the Firefox extension so you can […]

Smush.it is getting more and more buzz all over the internets. Now there’s even a song about it! Me and Nicole are pretty busy answering email, but a little slow to document the thing, I though I should at least shed some light on how the tool works by using some of the presentations. What […]

Since me and Nicole announced smush.it yesterday at Ajax Experience and thanks to Christian Heilmann posting it on Ajaxian and Yahoo Developer Network, this thing seems to have exploded! It’s all over the blogosphere, twitter-sphere and every other sphere. BTW, Chris never seizes to amaze – he posted the video on Ajaxian at 11:01 am […]