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If you run a website, you’ll know how important it is to keep file sizes down and optimize images, code, and files as much as possible. In this guide, I take a look at four image optimization tools, share their features, and compare them against each other.

Image Optimization Tools

I have chosen the following image optimization tools:

  • Smush.it
  • PNG Crush
  • PNG Out
  • RIOT


smush it01 Free Image Optimization Tools (PNG/JPG/GIF)

Smush.it is provided by Yahoo and now comes with YSlow (a tool used to determine bottlenecks in page-load time.) I’ve covered Smush.It before; here are some of its features:

  • High image compression rates
  • Handles all popular image types
  • Easy to use (as a Firefox extension
  • Comes bundled with other tools to help decrease page-load time
download64 Free Image Optimization Tools (PNG/JPG/GIF)

Download Smush.it (bundled with YSlow)

PNG Crush

I’ve used PNG Crush for a long time. On this post, I’ve included a registry hack you can use to “crush” images from the right-click context menu. PNG Crush doesn’t fair up as well as PNG Out (see below), but it’s simple to use and is convenient. Features include:

  • Medium to high compression
  • Only works with PNG images
  • No installation required

optimize pngcrush Free Image Optimization Tools (PNG/JPG/GIF)

download64 Free Image Optimization Tools (PNG/JPG/GIF)

Download PNG Crush


PNG Out faired the best in tests and does a good job or compressing PNG files. There are two ways you can use it: the command line version and the GUI (graphical user interface) version ($15 USD.)

I’ve made a registry hack you can use to automate image processing. Simply merge the registry key, put pngcrush.exe in the folder your compressing images in (or anywhere along the file path of the image(s)) , right click the folder, and click Compress Folder’s PNG Files.

Download PNG Out Registry Hack (<1 KB)

optimize pngout Free Image Optimization Tools (PNG/JPG/GIF)

download64 Free Image Optimization Tools (PNG/JPG/GIF)

Download PNG Out (PNGOUT.EXE)


RIOT is the most user-friendly tool to use out of the four, but faired up the worst, consistently, in tests. If you don’t want to deal with the command line, registry hacks, or a Firefox plug-in, this tool is for you. This tool also compresses most popular image types.

optimize riot Free Image Optimization Tools (PNG/JPG/GIF)

download64 Free Image Optimization Tools (PNG/JPG/GIF)

Download RIOT (Extended Version)


All four tools have their advantages. I’ve decided to rank the tools by different needs:

Ease of use: RIOT
Best for all image types: Smush.it
Best for PNG images: PNG Out
Best overall compression (PNG): PNG Out

Below you can see a comparison of file sizes after running compression, on the same file, with all four programs.

optimize comparison Free Image Optimization Tools (PNG/JPG/GIF)

 Free Image Optimization Tools (PNG/JPG/GIF)

About Rich

Rich is the owner and creator of Windows Guides; he spends his time breaking things on his PC so he can write how-to guides to fix the problems he creates.

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  • http://pulse.yahoo.com/_H4CGD2ZDPBRZCWTZY3BXW7EEW4 Luci

    By default RIOT uses a fast PNG compression. You have to enable best compression always for the final result.
    Also, RIOT always gives better results for palletized images if you visually decrease the number of colors until the picture starts to looks bad.
    You compared just the PNG compression. This is a format used on the web usually with low color images, not true color – and your test image was true color, more suitable to be a JPEG, which have been compressed better with RIOT.

    Look at this post in the section Improved PNG compression:

    RIOT has builtin support for pngout and it is very fast – the performance tests can confirm:

  • http://www.buraq-technologies.com/ ambreen11

    These are amazing image optimization tools.Optimization of graphics for the web is an art of creating attractive images with the smallest file size possible.Very helpful post.Thanks

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