diff --git a/components/style/properties/longhand/background.mako.rs b/components/style/properties/longhand/background.mako.rs
index 4ec1d3151e8..6071ffe4564 100644
--- a/components/style/properties/longhand/background.mako.rs
+++ b/components/style/properties/longhand/background.mako.rs
@@ -167,8 +167,8 @@ ${helpers.single_keyword("background-origin",
                          flags="APPLIES_TO_FIRST_LETTER APPLIES_TO_FIRST_LINE APPLIES_TO_PLACEHOLDER")}
 
 ${helpers.predefined_type("background-size", "BackgroundSize",
-    initial_value="computed::LengthOrPercentageOrAuto::Auto.into()",
-    initial_specified_value="specified::LengthOrPercentageOrAuto::Auto.into()",
+    initial_value="computed::BackgroundSize::auto()",
+    initial_specified_value="specified::BackgroundSize::auto()",
     spec="https://drafts.csswg.org/css-backgrounds/#the-background-size",
     vector=True,
     animation_value_type="BackgroundSizeList",
diff --git a/components/style/values/computed/background.rs b/components/style/values/computed/background.rs
index 1adf8ec0aa5..c618fb66c15 100644
--- a/components/style/values/computed/background.rs
+++ b/components/style/values/computed/background.rs
@@ -13,6 +13,16 @@ use values::generics::background::BackgroundSize as GenericBackgroundSize;
 /// A computed value for the `background-size` property.
 pub type BackgroundSize = GenericBackgroundSize<LengthOrPercentageOrAuto>;
 
+impl BackgroundSize {
+    /// Returns `auto auto`.
+    pub fn auto() -> Self {
+        GenericBackgroundSize::Explicit {
+            width: LengthOrPercentageOrAuto::Auto,
+            height: LengthOrPercentageOrAuto::Auto,
+        }
+    }
+}
+
 impl RepeatableListAnimatable for BackgroundSize {}
 
 impl ToAnimatedZero for BackgroundSize {
diff --git a/components/style/values/generics/background.rs b/components/style/values/generics/background.rs
index 09db669ad4f..1d3c2345b2f 100644
--- a/components/style/values/generics/background.rs
+++ b/components/style/values/generics/background.rs
@@ -24,12 +24,3 @@ pub enum BackgroundSize<LengthOrPercentageOrAuto> {
     #[animation(error)]
     Contain,
 }
-
-impl<L> From<L> for BackgroundSize<L>
-    where L: Clone,
-{
-    #[inline]
-    fn from(value: L) -> Self {
-        BackgroundSize::Explicit { width: value.clone(), height: value }
-    }
-}
diff --git a/components/style/values/specified/background.rs b/components/style/values/specified/background.rs
index 88a5f3152c7..c358feefaec 100644
--- a/components/style/values/specified/background.rs
+++ b/components/style/values/specified/background.rs
@@ -20,7 +20,7 @@ impl Parse for BackgroundSize {
             let height = input
                 .try(|i| LengthOrPercentageOrAuto::parse_non_negative(context, i))
                 .unwrap_or(LengthOrPercentageOrAuto::Auto);
-            return Ok(GenericBackgroundSize::Explicit { width: width, height: height });
+            return Ok(GenericBackgroundSize::Explicit { width, height });
         }
         let ident = input.expect_ident()?;
         (match_ignore_ascii_case! { &ident,
@@ -30,3 +30,13 @@ impl Parse for BackgroundSize {
         }).map_err(|()| SelectorParseError::UnexpectedIdent(ident.clone()).into())
     }
 }
+
+impl BackgroundSize {
+    /// Returns `auto auto`.
+    pub fn auto() -> Self {
+        GenericBackgroundSize::Explicit {
+            width: LengthOrPercentageOrAuto::Auto,
+            height: LengthOrPercentageOrAuto::Auto,
+        }
+    }
+}