Update readme

Author: joppuyo

README.md

@@ -82,14 +82,18 @@ Default value is `true` for lossy and `false` for lossless.
 
 ## Methods
 
-There's 3 different methods you can use: cjxl binary, ImageMagick extension and Vips extension. The library goes through each of the available methods and tries to use them. If none of the methods are available, an exception will be thrown.
+There are four different methods you can use: cjxl binary, cjxl system binary, ImageMagick extension and Vips extension. The library goes through each of the available methods and tries to use them. If none of the methods are available, an exception will be thrown.
 
 ### Cjxl binary
 
 This method executes the `cjxl` binary on the command line. It's the most compatible method and it supports the most features. However, the `proc_open` function needs to be enabled in the PHP installation since the library executes the binary on the command line. Some web hosts may disable this function for security reasons.
 
 Note: this library comes bundled with statically compiled version of the `cjxl` binary for Linux, macOS and Windows systems. The binary is bundled with all the required libraries which means it will work out of the box without the need to install any additional dependencies.
 
+### Cjxl system binary
+
+This is the same as the previous method but it executes the `cjxl` binary from system PATH. This means you need to install jpeg xl using your system package manager like homebrew or build jpeg xl from source and add the `cjxl` binary to your PATH variable.
+
 ### ImageMagick extension
 
 This method uses the ImageMagick library and its PHP extension Imagick. However, ImageMagick needs to be built with JXL delegate. In practice, this means you will need to install the libjxl library on the server. Then you will need to build ImageMagick from the source with the option `--with-jxl=yes`. Lastly, you will need to install the Imagick PHP extension. The ImageMagick extension does not support progressive encoding at the time. For an example how to compile ImageMagick with JPEG XL support, see [this Dockerfile](https://github.com/joppuyo/jpeg-xl-encode/blob/main/imagemagick.Dockerfile).