diff --git a/modules/markup/markdown/transform_image.go b/modules/markup/markdown/transform_image.go
index 0f9c69cae6..b86c9e3d41 100644
--- a/modules/markup/markdown/transform_image.go
+++ b/modules/markup/markdown/transform_image.go
@@ -44,6 +44,7 @@ func (g *ASTTransformer) transformImage(ctx *markup.RenderContext, v *ast.Image)
 		for _, attr := range v.Attributes() {
 			image.SetAttribute(attr.Name, attr.Value)
 		}
+		image.SetAttributeString("loading", []byte("lazy"))
 		for child := v.FirstChild(); child != nil; {
 			next := child.NextSibling()
 			image.AppendChild(image, child)
diff --git a/modules/markup/sanitizer.go b/modules/markup/sanitizer.go
index 384dd1fe94..aacc2536bf 100644
--- a/modules/markup/sanitizer.go
+++ b/modules/markup/sanitizer.go
@@ -108,6 +108,9 @@ func createDefaultPolicy() *bluemonday.Policy {
 	// Allow classes for emojis
 	policy.AllowAttrs("class").Matching(regexp.MustCompile(`^emoji$`)).OnElements("img")
 
+	// Allow attributes for images
+	policy.AllowAttrs("loading").Matching(regexp.MustCompile(`^lazy$`)).OnElements("img")
+
 	// Allow icons, emojis, chroma syntax and keyword markup on span
 	policy.AllowAttrs("class").Matching(regexp.MustCompile(`^((icon(\s+[\p{L}\p{N}_-]+)+)|(emoji)|(language-math display)|(language-math inline))$|^([a-z][a-z0-9]{0,2})$|^` + keywordClass + `$`)).OnElements("span")
 	policy.AllowAttrs("data-alias").Matching(regexp.MustCompile(`^[a-zA-Z0-9-_+]+$`)).OnElements("span")