diff --git a/tests/phpunit/tests/media.php b/tests/phpunit/tests/media.php
index b9b98dd..0e02897 100644
--- a/tests/phpunit/tests/media.php
+++ b/tests/phpunit/tests/media.php
@@ -33,6 +33,9 @@ function test_wp_lazy_load_content_media() {
 		// The following should not be modified because there already is a 'loading' attribute.
 		$img_eager = str_replace( ' />', ' loading="eager" />', $img );
 
+		// The following should not be modified either, because 'skip-lazy' is present.
+		$img_skiplazy = str_replace( 'class="', 'class="skip-lazy ', $img );
+
 		$content = '
 			<p>Image, standard.</p>
 			%1$s
@@ -46,11 +49,14 @@ function test_wp_lazy_load_content_media() {
 			<p>Image, with pre-existing "loading" attribute.</p>
 			%5$s
 
+			<p>Image, with "skip-lazy" set, not to be modified.</p>
+			%6$s
+
 			<p>Iframe, standard. Should not be modified by default.</p>
 			%4$s';
 
-		$content_unfiltered = sprintf( $content, $img, $img_xhtml, $img_html5, $iframe, $img_eager );
-		$content_filtered   = sprintf( $content, $lazy_img, $lazy_img_xhtml, $lazy_img_html5, $iframe, $img_eager );
+		$content_unfiltered = sprintf( $content, $img, $img_xhtml, $img_html5, $iframe, $img_eager, $img_skiplazy );
+		$content_filtered   = sprintf( $content, $lazy_img, $lazy_img_xhtml, $lazy_img_html5, $iframe, $img_eager, $img_skiplazy );
 
 		$this->assertSame( $content_filtered, wp_add_lazy_load_attributes( $content_unfiltered ) );
 	}
diff --git a/wp-lazy-loading.php b/wp-lazy-loading.php
index 0a3495d..b79e02f 100644
--- a/wp-lazy-loading.php
+++ b/wp-lazy-loading.php
@@ -62,7 +62,7 @@ function _wp_lazy_loading_initialize_filters() {
  * @return string Modified tag.
  */
 function _wp_lazy_loading_add_attribute_to_avatar( $avatar ) {
-	if ( in_array( 'img', wp_get_lazy_load_tags(), true ) && false === strpos( $avatar, ' loading=' ) ) {
+	if ( in_array( 'img', wp_get_lazy_load_tags(), true ) && false === strpos( $avatar, ' loading=' ) && false === strpos( $avatar, 'skip-lazy' ) ) {
 		$avatar = str_replace( '<img ', '<img loading="lazy" ', $avatar );
 	}
 
@@ -83,7 +83,7 @@ function _wp_lazy_loading_add_attribute_to_avatar( $avatar ) {
  * @return array Modified attributes.
  */
 function _wp_lazy_loading_add_attribute_to_attachment_image( $attr ) {
-	if ( in_array( 'img', wp_get_lazy_load_tags(), true ) ) {
+	if ( in_array( 'img', wp_get_lazy_load_tags(), true ) && ( ! array_key_exists( 'class', $attr ) || false === strpos( $attr['class'], 'skip-lazy' ) ) && ! array_key_exists( 'data-skip-lazy', $attr ) ) {
 		$attr['loading'] = 'lazy';
 	}
 
@@ -148,7 +148,7 @@ function wp_add_lazy_load_attributes( $content ) {
 	return preg_replace_callback(
 		'/<(' . implode( '|', $tags ) . ')(\s)[^>]+>/',
 		function( array $matches ) {
-			if ( ! preg_match( '/\sloading\s*=/', $matches[0] ) ) {
+			if ( ! preg_match( '/\sloading\s*=/', $matches[0] ) && false === strpos( $matches[0], 'skip-lazy' ) ) {
 				$tag   = $matches[1];
 				$space = $matches[2];