JavaScript Image Optimiser (JSIO)

Posted on by

So, I’ve embarked on a new mini project. It is kind of inspired by image sprites.

Image sprites are a great idea, but come with a whole bunch of issues that make them a bit of a pain to work with.

Firstly, most of the time you have to use markup to create an element in html to “hold” the image you wanted to display from your sprite. This is because if you actually set a sprite as the background image for a large html element you’re likely to see other images in the sprite as well. Because of this, you actually lose useful functionality that CSS gives you, like the ability to position, repeat and scale an image. Also, the markup you’ve created to hold the image exists for style purposes, which is bad.

Secondly, sprites can be a massive ball ache to maintain. If you’ve closely packed your images in a sprite for maximum efficiency and then one of your images needs to change size, you’re either going to have to move ALL images surrounding the image you have to update (and obviously then change all background-position properties for the images you’ve moved) or leave a space and put the updated image in a new position in your sprite.

How do you know which images in a sprite are used and which ones are dead? Since your images are referenced by coordinates, this sort of clean up becomes a nightmare and is actually a bit lot of a nightmare to create image sprites in the first place.

The goals of the project are to

  1. Reduce the number of http requests (and their associated header traffic) to the server and hence reduce the time it takes to load all images on a website and bandwidth footprint the site requires
  2. Create a solution that’ll alleviate some of the problems surrounding the creation and use of image sprites
  3. Do something cool

The JSIO project website has a pretty good explanation of how it works so I won’t bore you with the details here. However, as a brief overview, it packages all your image data in data uri format and you reference particular images by their filename rather than their coordinates.

The site actually uses the HTML5 file api to generate your resources file for you, which makes creating and maintaining your JSIO “sprite” really really easy.

I read *somewhere* that data uri encoded images can be up to 1/3 larger than corresponding image files, however with gzip encoding they can be only 0-3% larger (or less). My thesis is that for a site with many small images, JSIO could be more efficient and easier to maintain than having separate files or even an image sprite.

…I’m yet to prove or disprove this and I’ll be conducting some tests whose results I’ll post up here (even if they do prove JSIO to be useless).

Disclaimer: This is the first ever ALPHA release of JSIO – it works on the latest Firefox and Chrome but I haven’t even checked it in IE yet. It probably won’t work in IE yet. Also, the website needs some work for optimal display on mobile devices.

4,509 thoughts on “JavaScript Image Optimiser (JSIO)”

  7. В этой публикации мы обсуждаем современные методы лечения различных заболеваний. Читатели узнают о новых медикаментах терапиях и исследованиях которые активно применяются для лечения. Мы нацелены на то чтобы предоставить практические знания которые могут помочь в борьбе с недугами. Получить дополнительные сведения – вывод из запоя в стационаре в нижнем новгороде

  30. escorts en oaxaca Belek Fethiye Kusadasi escorts VIP escort Belek Fethiye Kusadasi mercedes cuban escort

  31. спасибо Вам за отзыв купить мефедрон скорость кокс Е.ать ты тиип.иди стукнись об стену..наxрен здесь такие большные люди нужны на форумеПо поводу фразы-настраиваися на спид..На работу таким Xодить надо axaxaxМагаз на высшем уровне Тут и говорить нехуй. Хочешь качество закупись тут Мир бро

  34. В этом обзоре мы обсудим современные методы борьбы с зависимостями включая медикаментозную терапию и психотерапию. Мы представим последние исследования и их результаты чтобы читатели могли быть в курсе наиболее эффективных подходов к лечению и поддержке. Ознакомиться с деталями – капельница после запоя

  39. This is really interesting You are a very skilled blogger. Ive joined your feed and look forward to seeking more of your excellent post. Also Ive shared your website in my social networks tada-gaming.mobi

  40. I loved as much as you will receive carried out right here. The sketch is tasteful your authored material stylish. nonetheless you command get bought an shakiness over that you wish be delivering the following. unwell unquestionably come further formerly again as exactly the same nearly very often inside case you shield this increase. tada-gaming.mobi

  41. Thank you a lot for sharing this with all of us you really recognize what youre talking approximately Bookmarked. Kindly additionally discuss with my site =). We could have a hyperlink exchange contract among us tada-gaming.mobi

  43. В обзорной статье вы найдете собрание важных фактов и аналитики по самым разнообразным темам. Мы рассматриваем как современные исследования, так и исторические контексты, чтобы вы могли получить полное представление о предмете. Погрузитесь в мир знаний и сделайте шаг к пониманию!
    Полная информация здесь – вывод из запоя нарколог 24

  45. Thank you for the auspicious writeup. It in truth was once a amusement account it. Glance complicated to far delivered agreeable from you By the way how could we be in contact? tada gaming slots

  46. Эта статья освещает различные аспекты освобождения от зависимости и пути к выздоровлению. Мы обсуждаем важность осознания своей проблемы и обращения за помощью. Читатели получат практические советы о том как преодолевать трудности и строить новую жизнь без зависимости. Получить дополнительную информацию – запой стационар

  47. отличный магазин все всегда ровно купить мефедрон скорость кокс 21 мая заказал -23 получил трек.все ок жду посылспасибо Хороший магазин берите тут

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>