Getting error when compressing PNG image – imagepng(): gd-png: fatal libpng error: bad parameters to zlib

I am getting an error in php when I try to compress my png images. Here is my code:

public function compress() {
   $filePath = "/path/image.png";
   $image = @imagecreatefrompng($filePath);
   if (!$image) return;
   
   // compress with 60% of quality
   imagepng($image, $filePath, 60);
}

Here is the error message:

imagepng(): gd-png: fatal libpng error: bad parameters to zlib

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I am getting this error when I execute "imagepng" function. Why I am getting this error? thank you

>Solution :

The quality parameter of the imagepng() function only takes values from 0 – 9.

• 0 = no compression
• 9 = max compression.

Which means the function can’t use your input 60

Reference:

https://www.php.net/manual/en/function.imagepng says:

quality: Compression level: from 0 (no compression) to 9. The default (-1) uses the zlib compression default. For more information see the » zlib manual.