Default image driver to vips

Switch IMAGE_DRIVER default from gd to vips in config/image.php and the
shipped .env examples. libvips is faster, lower-memory, and has strong
WebP/AVIF support; both libvips and the php-vips extension ship in the
official Docker image. ImageDriverManager already maps 'vips' to the
installed Intervention Vips driver, so no code change is needed.

.env.testing stays on gd because the CI test runners install the gd
extension, not php-vips.

.env.docker.example

@@ -17,7 +17,7 @@ ENABLE_CONFIG_CACHE="true"
 INSTANCE_DISCOVER_PUBLIC="true"
 
 # Media Configuration
-IMAGE_DRIVER=gd # vips, gd, imagick
+IMAGE_DRIVER=vips # vips, gd, imagick
 PF_OPTIMIZE_IMAGES="true"
 IMAGE_QUALITY="80"
 MAX_PHOTO_SIZE="15000"

.env.example

@@ -13,7 +13,7 @@ ENABLE_CONFIG_CACHE="true"
 INSTANCE_DISCOVER_PUBLIC="true"
 
 # Media Configuration
-IMAGE_DRIVER=gd # vips, gd, imagick
+IMAGE_DRIVER=vips # vips, gd, imagick
 PF_OPTIMIZE_IMAGES="true"
 IMAGE_QUALITY="80"
 MAX_PHOTO_SIZE="15000"

config/image.php

@@ -7,17 +7,21 @@ return [
     | Image Driver
     |--------------------------------------------------------------------------
     |
-    | Intervention Image supports “GD Library” and “Imagick” to process images
-    | internally. Depending on your PHP setup, you can choose one of them.
+    | Intervention Image supports "libvips", "GD Library" and "Imagick" to
+    | process images internally. Depending on your PHP setup, you can choose
+    | one of them. libvips is the default: it is significantly faster and uses
+    | far less memory than GD/Imagick, and has strong support for modern
+    | formats such as WebP and AVIF. It requires the php-vips extension and
+    | libvips to be installed (both ship in the official Pixelfed image).
     |
     | Included options:
+    |   - vips    = \Intervention\Image\Drivers\Vips\Driver::class
     |   - gd      = \Intervention\Image\Drivers\Gd\Driver::class
     |   - imagick = \Intervention\Image\Drivers\Imagick\Driver::class
-    |   - vips    = \Intervention\Image\Drivers\vips\Driver::class
     |
     */
 
-    'driver' => env('IMAGE_DRIVER', 'gd'),
+    'driver' => env('IMAGE_DRIVER', 'vips'),
 
     /*
     |--------------------------------------------------------------------------