refactor(docs): add libvips install reference

README.md

@@ -63,12 +63,20 @@ go get -u github.com/h2non/bimg
 
 ### libvips
 
+Follow `libvips` installation instructions:
+
+[https://libvips.github.io/libvips/install.html](https://libvips.github.io/libvips/install.html)
+
+##### Installation script
+
+**Note**: install script is officially deprecated, it might not work as expected. We recommend following [libvips install](https://libvips.github.io/libvips/install.html) instructions.
+
 Run the following script as `sudo` (supports OSX, Debian/Ubuntu, Redhat, Fedora, Amazon Linux):
 ```bash
 curl -s https://raw.githubusercontent.com/h2non/bimg/master/preinstall.sh | sudo bash -
 ```
 
-If you wanna take the advantage of [OpenSlide](http://openslide.org/), simply add `--with-openslide` to enable it:
+If you want to take the advantage of [OpenSlide](http://openslide.org/), simply add `--with-openslide` to enable it:
 ```bash
 curl -s https://raw.githubusercontent.com/h2non/bimg/master/preinstall.sh | sudo bash -s --with-openslide
 ```

preinstall.sh

@@ -1,5 +1,9 @@
 #!/bin/bash
 
+#
+# NOTE: deprecated! Try libvips installation: https://libvips.github.io/libvips/install.html
+#
+
 vips_version_minimum=8.9.2
 vips_version_latest_major_minor=8.9
 vips_version_latest_patch=2