When converting images in JPG (JPEG) and PNG formats using the PHP GD library, the quality of the output image is adjusted as follows:
imagejpeg
0 (lowest quality, smallest size) - 100 (highest quality, largest size).
The default is about 75.
imagepng
0 (no compression) - 9.
Default zlib compression
imagegif
Quality adjustment is not available
imagewbmp
Quality adjustment is not available
GD Graphics Library
PHP: GD - Manual
https://www.php.net/manual/en/book.image.php
References
PHP: Hypertext Preprocessor
https://www.php.net
Understanding PHP Absolute and Relative Paths
https://www.ppcle.com/post/php-realpath/
