diff --git a/library/HTMLPurifier/CSSDefinition.php b/library/HTMLPurifier/CSSDefinition.php
index 47dfd1f6..21f1a589 100644
--- a/library/HTMLPurifier/CSSDefinition.php
+++ b/library/HTMLPurifier/CSSDefinition.php
@@ -220,15 +220,25 @@ class HTMLPurifier_CSSDefinition extends HTMLPurifier_Definition
             array(
                 new HTMLPurifier_AttrDef_CSS_Length('0'),
                 new HTMLPurifier_AttrDef_CSS_Percentage(true),
-                new HTMLPurifier_AttrDef_Enum(array('auto'))
+                new HTMLPurifier_AttrDef_Enum(array('auto', 'initial', 'inherit'))
+            )
+        );
+        $trusted_min_wh = new HTMLPurifier_AttrDef_CSS_Composite(
+            array(
+                new HTMLPurifier_AttrDef_CSS_Length('0'),
+                new HTMLPurifier_AttrDef_CSS_Percentage(true),
+                new HTMLPurifier_AttrDef_Enum(array('initial', 'inherit'))
+            )
+        );
+        $trusted_max_wh = new HTMLPurifier_AttrDef_CSS_Composite(
+            array(
+                new HTMLPurifier_AttrDef_CSS_Length('0'),
+                new HTMLPurifier_AttrDef_CSS_Percentage(true),
+                new HTMLPurifier_AttrDef_Enum(array('none', 'initial', 'inherit'))
             )
         );
         $max = $config->get('CSS.MaxImgLength');
 
-        $this->info['min-width'] =
-        $this->info['max-width'] =
-        $this->info['min-height'] =
-        $this->info['max-height'] =
         $this->info['width'] =
         $this->info['height'] =
             $max === null ?
@@ -245,6 +255,38 @@ class HTMLPurifier_CSSDefinition extends HTMLPurifier_Definition
                     // For everyone else:
                     $trusted_wh
                 );
+        $this->info['min-width'] =
+        $this->info['min-height'] =
+            $max === null ?
+                $trusted_min_wh :
+                new HTMLPurifier_AttrDef_Switch(
+                    'img',
+                    // For img tags:
+                    new HTMLPurifier_AttrDef_CSS_Composite(
+                        array(
+                            new HTMLPurifier_AttrDef_CSS_Length('0', $max),
+                            new HTMLPurifier_AttrDef_Enum(array('initial', 'inherit'))
+                        )
+                    ),
+                    // For everyone else:
+                    $trusted_min_wh
+                );
+        $this->info['max-width'] =
+        $this->info['max-height'] =
+            $max === null ?
+                $trusted_max_wh :
+                new HTMLPurifier_AttrDef_Switch(
+                    'img',
+                    // For img tags:
+                    new HTMLPurifier_AttrDef_CSS_Composite(
+                        array(
+                            new HTMLPurifier_AttrDef_CSS_Length('0', $max),
+                            new HTMLPurifier_AttrDef_Enum(array('none', 'initial', 'inherit'))
+                        )
+                    ),
+                    // For everyone else:
+                    $trusted_max_wh
+                );
 
         $this->info['text-decoration'] = new HTMLPurifier_AttrDef_CSS_TextDecoration();
 
diff --git a/tests/HTMLPurifier/AttrDef/CSSTest.php b/tests/HTMLPurifier/AttrDef/CSSTest.php
index 2d938cec..7ad5788e 100644
--- a/tests/HTMLPurifier/AttrDef/CSSTest.php
+++ b/tests/HTMLPurifier/AttrDef/CSSTest.php
@@ -64,7 +64,9 @@ class HTMLPurifier_AttrDef_CSSTest extends HTMLPurifier_AttrDefHarness
         $this->assertDef('width:-50px;', false);
         $this->assertDef('min-width:50%;');
         $this->assertDef('min-width:50px;');
-        $this->assertDef('min-width:auto;');
+        $this->assertDef('min-width:auto;', false);
+        $this->assertDef('min-width:initial;');
+        $this->assertDef('min-width:inherit;');
         $this->assertDef('min-width:-50px;', false);
         $this->assertDef('min-width:50ch;');
         $this->assertDef('min-width:50rem;');