How to use the command 'pngcrush' (with examples)
This article provides a guide on using the ‘pngcrush’ command with different use cases.
Command Description
The ‘pngcrush’ command is a PNG compression utility that allows you to compress PNG files. It optimizes the files by reducing their size without losing any essential data. It offers various algorithms and options to customize the compression process.
Use case 1: Compress a PNG file
Code:
pngcrush in.png out.png
Motivation:
This use case is useful when you want to compress a single PNG file to reduce its size without impacting its quality. Compressing PNG files is essential for optimizing web pages and reducing load times.
Explanation:
- ‘in.png’: This argument specifies the input PNG file that needs to be compressed.
- ‘out.png’: This argument specifies the output file where the compressed PNG will be saved.
Example Output:
After running the command, the input PNG file ‘in.png’ will be compressed, and the resulting compressed PNG will be saved as ‘out.png’.
Use case 2: Compress all PNGs and output them to the specified directory
Code:
pngcrush -d path/to/output *.png
Motivation:
This use case is helpful when you have multiple PNG files in a directory that you want to compress all at once. It saves time by compressing all PNGs in one go and allows you to specify the directory where the compressed files should be saved.
Explanation:
- ‘-d path/to/output’: This argument specifies the directory where the compressed PNG files will be saved.
- ‘*.png’: This wildcard represents all PNG files in the current directory.
Example Output:
When executed, the command will compress all PNG files in the current directory and save the compressed files to the specified output directory.
Use case 3: Compress PNG file with all 114 available algorithms and pick the best result
Code:
pngcrush -rem allb -brute -reduce in.png out.png
Motivation:
Sometimes, you may want to achieve the highest possible compression by trying out all available algorithms. This use case allows you to compress a PNG file using all 114 algorithms and select the best result.
Explanation:
- ‘-rem allb’: This option removes all PNG chunks including bad or unoptimized ones.
- ‘-brute’: This option enables brute-force compression by trying all remaining options.
- ‘-reduce’: This option reduces the color precision of the PNG image.
Example Output:
After executing the command, the PNG file ‘in.png’ will be compressed using all 114 algorithms. The command will then select the best result and save the compressed PNG as ‘out.png’.
Conclusion:
The ‘pngcrush’ command provides a powerful utility for compressing PNG files, allowing you to reduce their size without losing any important data. By understanding the different use cases and options available, you can effectively optimize PNG files for various purposes, such as improving website performance and reducing bandwidth usage.
