Add support for $config->imageSizes setting which lets you name and predefine image sizes/options that you can later refer to by name on any $image->size() call (via the width argument).

wire/config.php

@@ -616,6 +616,40 @@ $config->fileContentTypes = array(
 	'mp3' => 'audio/mpeg',
 	);
 
+/**
+ * Named predefined image sizes and options
+ *
+ * Specify associative arrays of predefined image sizes indexed by name.
+ * Each item should have at least 'width' and 'height' indexes. But they can also have any
+ * other option accepted by the `Pageimage::size()` method `$options` argument.
+ *
+ * You can use your defined sizes by name in a Pageimage::size() call by specifying the
+ * size name rather than the `$width` argument, like this:
+ * ~~~~~~
+ * $image = $page->images->first();
+ * $landscape = $image->size('landscape');
+ * echo "<img src='$landscape->url' alt='$landscape->description' />";
+ * ~~~~~~
+ * Feel free to completely overwrite the default $config->imageSizes in your /site/config.php
+ * file * as this particular setting is not used by the core.
+ *
+ * @var array
+ * @since 3.0.151
+ *
+ */
+$config->imageSizes = array(
+	// Example 1: Landscape (try this one if you want to test the feature)
+	'landscape' => array('width' => 600, 'height' => 300),
+	
+	// Example 2: Thumbnails in admin (260 height, proportional width) 
+	// 'admin' => array('width' => 0, 'height' => 260),
+	
+	// Example 3: Portrait, with additional options: 
+	// 'portrait' => array('width' => 300, 'height' => 500, 'quality' => 80, 'suffix' => 'portrait'),
+	
+	// Example 4: Square size cropping towards (preserving) top/center (north): 
+	// 'squareNorth' => array('width' => 400, 'height' => 400, 'cropping' => 'north'),
+);
 
 /**
  * Image sizer options
@@ -1318,7 +1352,16 @@ $config->adminEmail = '';
  * @var string
  * 
  */
-$config->fatalErrorHTML = "<p style='background:crimson;color:white;padding:0.5em;font-family:sans-serif;'><b>{message}</b><br /><br /><small>{why}</small></p>";
+$config->fatalErrorHTML = "<p style='background:crimson;color:white;padding:1em;font-family:sans-serif;font-size:16px;line-height:20px;clear:both'>{message}<br /><br /><small>{why}</small></p>";
+
+/**
+ * HTTP code to send for fatal error (typically 500 or 503)
+ * 
+ * @var int
+ * @since 3.0.151
+ * 
+ */
+$config->fatalErrorCode = 500;
 
 /**
  * Settings for modal windows

wire/core/Config.php

@@ -40,6 +40,7 @@
  * 
  * @property bool $protectCSRF Enables CSRF (cross site request forgery) protection on all PW forms, recommended for security. #pw-group-HTTP-and-input
  * 
+ * @property array $imageSizes Predefined image sizes (and options) indexed by name. See /wire/config.php for example. (3.0.151+) #pw-group-images
  * @property array $imageSizerOptions Options to set image sizing defaults. Please see the /wire/config.php file for all options and defaults. #pw-group-images
  * @property array $webpOptions Options for webp images. Please see /wire/config.php for all options. #pw-group-images
  * 
@@ -135,6 +136,7 @@
  * @property bool $logIP Include IP address in logs, when applicable? #pw-group-admin
  * @property string $defaultAdminTheme Default admin theme: AdminThemeDefault or AdminThemeReno #pw-group-admin
  * @property string $fatalErrorHTML HTML used for fatal error messages in HTTP mode. #pw-group-system
+ * @property int $fatalErrorCode HTTP code to send on fatal error (typically 500 or 503). #pw-group-system
  * @property array $modals Settings for modal windows #pw-group-admin
  * @property array $preloadCacheNames Cache names to preload at beginning of request #pw-group-system
  * @property bool $allowExceptions Allow Exceptions to propagate? (default=false, specify true only if you implement your own exception handler) #pw-group-system

wire/core/Pageimage.php

@@ -24,7 +24,7 @@
  * ~~~~~
  * #pw-body
  * 
- * ProcessWire 3.x, Copyright 2018 by Ryan Cramer
+ * ProcessWire 3.x, Copyright 2020 by Ryan Cramer
  * https://processwire.com
  *
  * @property-read int $width Width of image, in pixels.
@@ -480,7 +480,11 @@ class Pageimage extends Pagefile {
 				} else {
 					$info = @getimagesize($this->filename);
 				}
-				if($info) {
+				if((!$info || empty($info[0])) && !empty($this->sizeOptions['_width'])) {
+					// on fail, fallback to size options that were requested for the image (if available)
+					$imageInfo['width'] = $this->sizeOptions['_width'];
+					$imageInfo['height'] = $this->sizeOptions['_height'];
+				} else if($info) {
 					$imageInfo['width'] = $info[0];
 					$imageInfo['height'] = $info[1];
 				}
@@ -565,6 +569,9 @@ class Pageimage extends Pagefile {
 	 * 
 	 * // Output thumbnail
 	 * echo "<img src='$thumb->url' />";
+	 * 
+	 * // Create image of size predefined in $config->imageSizes (3.0.151+)
+	 * $photo = $image->size('landscape'); 
 	 * ~~~~~
 	 * 
 	 * **About the $options argument**
@@ -625,8 +632,8 @@ class Pageimage extends Pagefile {
 	 * #pw-group-common
 	 * #pw-hooks
 	 *
-	 * @param int $width Target width of new image
-	 * @param int $height Target height of new image
+	 * @param int|string $width Target width of new image or (3.0.151+) specify prefined image size name
+	 * @param int|array $height Target height of new image or (3.0.151+) options array if no height argument needed
 	 * @param array|string|int $options Array of options to override default behavior: 
 	 *  - Specify `array` of options as indicated in the section above. 
 	 *  - Or you may specify type `string` containing "cropping" value.
@@ -636,8 +643,21 @@ class Pageimage extends Pagefile {
 	 *  If the specified dimensions/options are the same as the original, then the original will be returned.
 	 *
 	 */
-	public function size($width, $height, $options = array()) {
-		if(!is_array($options)) $options = $this->sizeOptionsToArray($options);
+	public function size($width, $height = 0, $options = array()) {
+		
+		if(is_array($height)) {
+			$options = $height;
+			$height = 0;
+		}
+		
+		if(!is_array($options)) {
+			$options = $this->sizeOptionsToArray($options);
+		}
+		
+		if(is_string($width) && $width && !ctype_digit($width)) {
+			// named image size
+			return $this->sizeName($width, $options);
+		}
 
 		if($this->wire('hooks')->isHooked('Pageimage::size()')) {
 			$result = $this->__call('size', array($width, $height, $options)); 
@@ -946,6 +966,31 @@ class Pageimage extends Pagefile {
 		return $this->size($width, $height, $options); 
 	}
 
+	/**
+	 * Return image of size indicated by predefined setting
+	 * 
+	 * Settings for predefined sizes can be specified in `$config->imageSizes` array. 
+	 * Each named item in this array must contain at least 'width' and 'height, but can also
+	 * contain any other option from the `Pageimage::size()` argument `$options`. 
+	 * 
+	 * @param string $name Image size name
+	 * @param array $options Optionally add or override options defined for size. 
+	 * @return Pageimage
+	 * @since 3.0.151
+	 * @throws WireException If given a $name that is not present in $config->imageSizes
+	 * 
+	 */
+	public function sizeName($name, array $options = array()) {
+		$sizes = $this->wire('config')->imageSizes; 
+		if(!isset($sizes[$name])) throw new WireException("Unknown image size '$name' (not in \$config->imageSizes)"); 
+		$size = $sizes[$name];
+		$options = array_merge($size, $options);
+		unset($options['width'], $options['height']); 
+		if(!isset($size['width'])) $size['width'] = 0;
+		if(!isset($size['height'])) $size['height'] = 0;
+		return $this->size((int) $size['width'], (int) $size['height'], $options);
+	}
+
 	/**
 	 * Create a crop and return it as a new Pageimage.
 	 *