Warning: libpng warning: iCCP: Known incorrect sRGB profile

Question

I try to load a PNG image using SDL but the program doesn't run and I get this error in the console

libpng WARNING: iCCP: Known incorrect sRGB profile

Why does this warning appear? What should I do to resolve this issue?

Answer 1

Remove incorrect sRGB profiles from png files using pngcrush:

pngcrush -ow -rem allb -reduce file.png

• -ow will overwrite the input file
• -rem allb will remove all auxiliary blocks except tRNS and gAMA
• -reduce Perform lossless color type or bit depth reduction

In the console output you should see Removed the sRGB chunk, and possibly more messages about chunk removal. You'll end up with a smaller, optimized PNG file. Since this command will overwrite the original file, make sure to create a backup or use version control.

Answer 2

Some applications treat warnings as errors; if you are using such an application, you must remove this block. You can do this using any kind of PNG editor, such as ImageMagick.

Using Windows CMD prompt, you need to cd (change directory) to the folder containing the images you want to focus on before you can use the commands listed below.

Libpng-1.6 has stricter checks for ICC profiles than previous versions; you can ignore the warning. To get rid of it, remove the iCCP block from the PNG image.

convert in.png out.png

To remove invalid iCCP blocks from all PNG files in a folder (directory), you can use mogrify from ImageMagick:

mogrify *.png

This requires that your ImageMagick is built with libpng16. You can easily check it by running:

convert -list format | grep PNG

If you want to find out which files need to be repaired instead of blindly processing them all, you can run

pngcrush -n -q *.png

Where -n means not to rewrite the file, -q means to suppress most output except warnings. Sorry, there is no option yet in pngcrush to suppress everything except warnings.

Note: You must have pngcrush installed.

---

Binary versions of ImageMagick are located here

---

For Android projects (Android Studio), navigate to the res folder.

For example:

C:\{your_project_folder}\app\src\main\res\drawable-hdpi\mogrify *.png