13 Free PNG image optimization and compression tools

Source: Internet
Author: User
Tags tinypng

There are many different types of image formats, the most common on the Internet are JPEG, GIF, BMP, TIFF, and PNG. Each image format has its own purpose, such as GIF is used for animation, JPEG is used for high-definition pictures, this image will be saved or resized automatically reduce its sharpness, and our favorite PNG is best for small and transparent images. Another great advantage of PNG files is that these files are lossless, which means that you can compress PNG files without losing clarity.

You can easily find the tools to compress PNG files on the Internet, and most, rather than all, will generate files of different sizes due to different algorithms, unless the tools use the same library or technology to generate files of the same size. Minimizing the size of the image file can save transmission bandwidth, reduce download time, and even achieve higher performance points for Google page access, because "optimized image" is the first choice to achieve these goals. In this document, we will test 13 free PNG compression tools (with online compression tools, command-line compression tools, and desktop compression tools) to find the tool that produces the smallest file size.

We will use the 13 free image compression tools listed below to compress a 8-bit and 24-bit PNG file. The tools listed include command-line tools, desktop programs, and online services. Command-line tools are more flexible when it comes to automating large numbers of files, but it requires you to type all the commands, including command options and Paths. Desktop tools are easier to use, and the program has a graphical user interface, which usually takes just a few mouse clicks to complete compression. Finally, the online service, which is an application located on the remote server, is performed on the remote server and the user does not need to install any third-party software.

Command-line tool


Advpng is part of the AdvanceCOMP app, AdvanceCOMP contains multiple PNG, ZIP, MNG and GZ files are re-compressed by the free tool. Advpng has not been updated since 2005, but its compression speed and results have surprised you. It takes a little longer to compress older machines with slower hardware configurations, and a new multicore CPU can generate surprising results in just one second. The maximum compression command for

Advpng is as follows:

advpng.exe-z4 file.png
Click here to download AdvanceCOMP.

2.OptiPNG The

OptiPNG is another open source command-line PNG compression tool that supports both the Windows operating system and the Linux operating system.

Its stable and development versions are available for download. It is important to note that the maximum compression command line for stable and development versions is slightly different. The maximum compression ratio for the

OptiPNG stable version is-o7, while the development version is-O6. If you try to force-o7 on a development version,

Then you will still get the same size file as the-o6. The command for the maximum compression of the

OptiPNG stable version is as follows:

Optipng.exe-o7 file.png
optipng The maximum compression of the development version is as follows:
optipng-hg-latest-win32-o6 file.png
Click here to download the optipng.


Pngcrush is also a command-line tool that attempts to optimize PNG images using different compression ratios and PNG filtering methods. If you use the-brute option, then Pngcrush will test this image in 148 ways to find the compression method that works best for this image.

The maximum compression command for Pngcrush is as follows:

pngcrush.exe-brute file.png output.png
Click here to download Pngcrush.


Pngoptimizer has a simple graphical user interface program, so all you have to do is drag the image you want to compress into the window of the program, and Pngoptimizer is a command-line tool that you can run at the command line prompt. In addition to reducing the PNG file size by removing errors or useless information on PNG, it can also handle animated PNG formats (APNG) that are still uncommon today. In order to optimize the image file, you either specify an exact file name or use the * number wildcard character.

The maximum compression command for PNGOPTIMIZERCL is as follows:

pngoptimizercl.exe-file: "File.png"
click here to download PNGOPTIMIZERCL.



Unlike most command-line PNG optimization tools, PNGOut is not open source because its compression algorithms have been incorporated into their commercial GUI version pngoutwin, and Pngoutwin supports both batch processing and multi-core CPUs. Although it is not open source, you can still find binaries on windows, Linux, BSD, and Mac OS X that have been compiled. PNGOut is one of the easiest compression tools to use. Because, by default, no command-line option is specified, it uses the Xtreme compression algorithm with the highest compression ratio.

The PNGOut maximum compression command is as follows:

pngout.exe file.png
Click here to download PNGOut.


Scriptpng is actually a batch file that can be optimized for image files using up to 10 PNG compression algorithms. Selecting the Super Option number 9 will use the maximum compression algorithm that generates the smallest file, but it will take more time to complete the optimization process. All you need to do is drag the png file from explore to the program, then choose one of the 9 options.

Click here to download Scriptpng.


Truepng Unlike some of the PNG compression tools described above, it only supports PNG files. Some of the PNG compression tools described above try to convert other image file formats, such as JPEG and GIP, in PNG format, in cases where smaller files are available.

The Truepng maximum compression command is as follows:

TruePNG.exe input.png/o Max

Click here to download Truepng.

Desktop software


Pnggauntlet is actually a front-end tool that uses three different PNG optimization tools (PNGOut, OptiPNG, and deflopt) to compress PNG files multiple times, rather than just using a single tool as seen. The use of three compression tools does increase the time it takes to compress PNG files, but it certainly generates smaller files. A good feature of Pnggauntlet is the ability to automatically queue multiple files when you are doing batch processing. The default option in the Tools menu is already the best (maximum) compression setting, unless you intend to keep the PNG metadata, use the grayscale color mode, and so on before changing the value. Running this software requires installing Microsoft's. NET Framework 4.

Click here to download Pnggauntlet.

Online Service


Kraken is a free online image optimization tool that supports both lossless optimization mode and lossy optimization mode. In order to optimize the image file, you either choose an image source file on your computer, or paste some URLs. The PNG image file is then "kraked" and the resulting file is uploaded to their own CDN for temporary 1-hour storage after processing is complete. One of the great things that Kraken.io does is that you can extend Chrome and Firefox with a limited, free API. Paid plans that use the Advanced API will be released within a few weeks. Based on our testing, Kraken's free compression is comparable to the ultimate compression of paid punypng.

Click here to visit Kraken.


Pngoptimize.com is a very simple site that allows you to upload and compress image files up to 3MB. Click the browse button to find the image file to upload, then click on the Optimization button very close to the ad bar, from the test results, we can determine that pngoptimizer.com is using OptiPNG for PNG file compression.

Click here to visit pngoptimizer.com


Punypng has gained a lot of attention because, compared to other online publishers, Punypng has removed more bytes. This site provides free compression, and when you register as a professional user, you will automatically use a very strong and lossy compression algorithm. To compress the PNG image file, click the Upload button, free users can choose to upload 15 files each time, each file maximum is 150KB. and professional users can choose to upload 50 files each time, each file maximum is 500KB.

Click here to access the punypng.

smush.it .


Tinypng in order to achieve a smaller file size for lossy compression, although the quality of a slight decline, but bare eyes do not come out. So if you have a 24-bit PNG image, the compression under Tinypng will turn into a 8-bit PNG file. It supports processing 20 pictures at a time, each size within 3MB.

Visit tinypng

PNG compression test

Two 8-bit PNG files compression test results

Compression test results for two 24-bit PNG files

Summary: scriptpng can generate the smallest compressed file for both 24-bit PNG files and 8-bit PNG files. Note: Scriptpng is just a script that uses several compression tools to optimize PNG files more than once, so it takes longer to process than other command-line tools. Also note that although pngout is really good at compressing 8-bit PNG files, the compression of 24-bit PNG files is the worst. The

is not mentioned above, but we are sure that the online service pngoptimizer.com uses optipng for PNG file compression because both methods produce exactly the same size files in all four Tests performed above. Our tests also show that the Kraken graphics optimizer generates files of the same size as the Punypng limit compression method that only punpng paid users can use.

prompts for using the command line user. If you need to use command-line tools frequently and don't want to optimize or compress PNG images every time you repeat the full command line, here's a simple way to do it with just two clicks. What you need to do is add a new action in the content directory, which is only displayed when you click on the PNG file.

1. Download the Extman, unzip and execute the executable;

2. The default program language is German, you only need to click on the United States flag table, so that the window will switch to English;

3. Scroll down the scroll bar to find the extension "PNG", the file type is " PNG image ";

4. Double-click the PNG extension name and click the New Action button.

5. You can enter anything in the process bar, either the name of the PNG compression tool or just compress if you want to only need one word on the command line.


6. As for the "Application for processing" box, all you need to do is enter the following command line depending on the command line tool you are using. If you have not placed the command-line tool at the root of the C: \ Disk, change the path where the tool is located.

  • Advpng:c:\advpng.exe-z4 "%1" (will overwrite existing files)
  • Optipng:c:\optipng.exe-o7-backuup "%1" (to create a backup file for an existing file, increase the. bak extension)
  • pngcrush:c:\pngcrush.exe-brute-e_compressed "%1" (Save the compressed PNG file with the file name of the original file name plus _compressed.png)
  • pngoptimizercl:c:\pngoptimizercl.exe-backupoldpngfiles-file:%1 "(Back up the original PNG file by adding an underscore character to the file name)
  • Pngout:c:\pngout.exe "%1" Out.png (save compressed PNG file as Out.png)
  • Scriptpng:c:\scriptpng\scriptpng.cmd "%1" (press the Number 9 key, then overwrite the existing PNG file)
  • Truepng:c:\truepng.exe "%1"/O max/out out.png (Saves the compressed PNG file as Out.png)

7. Click the Save button to close the Action window and then click the Save button to close the edit window.

8. Whenever you click the right mouse button on a PNG file, you will see a more command on the popup menu, which is used to compress the PNG file.

English Original: Free Tools to Optimize and Compress PNG to Reduce Image Size

13 Free PNG image optimization and compression tools

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