diff --git a/Tests/OutputFilterTest.php b/Tests/OutputFilterTest.php
index e702139d..4f6693f4 100644
--- a/Tests/OutputFilterTest.php
+++ b/Tests/OutputFilterTest.php
@@ -215,6 +215,18 @@ public function testStripImages()
 			$this->object->stripImages('Hello <img src="wave.jpg"> I am waving at you.'),
 			'Should remove img tags'
 		);
+
+		$this->assertEquals(
+			'Hello  I am waving at you.',
+			$this->object->stripImages('Hello <IMG src="wave.jpg"> I am waving at you.'),
+			'Should remove uppercase img tags'
+		);
+
+		$this->assertEquals(
+			'Hello  I am waving at you.',
+			$this->object->stripImages('Hello <<img>IMg src="wave.jpg"> I am waving at you.'),
+			'Should remove nested tags'
+		);
 	}
 
 	/**
@@ -229,5 +241,19 @@ public function testStripIframes()
 			),
 			'Should remove iFrame tags'
 		);
+
+		$this->assertEquals(
+			'Hello  I am waving at you.',
+			$this->object->stripIframes('Hello <IFrame src="http://player.vimeo.com/video/37576499" width="500"' .
+				' height="281" frameborder="0" webkitAllowFullScreen mozallowfullscreen allowFullScreen></iframe> I am waving at you.'),
+			'Should remove uppercase iFrame tags'
+		);
+
+		$this->assertEquals(
+			'Hello  I am waving at you.',
+			$this->object->stripIframes('Hello <<iframe>iframe src="http://player.vimeo.com/video/37576499" width="500"' .
+				' height="281" frameborder="0" webkitAllowFullScreen mozallowfullscreen allowFullScreen></iframe> I am waving at you.'),
+			'Should remove nested iFrame tags'
+		);
 	}
 }
diff --git a/src/OutputFilter.php b/src/OutputFilter.php
index d78e8032..996393d0 100644
--- a/src/OutputFilter.php
+++ b/src/OutputFilter.php
@@ -275,7 +275,12 @@ public static function setLanguage(Language $language): void
 	 */
 	public static function stripImages($string)
 	{
-		return preg_replace('#(<[/]?img.*>)#U', '', $string);
+		while (preg_match('#(<[/]?img.*>)#Ui', $string))
+		{
+			$string = preg_replace('#(<[/]?img.*>)#Ui', '', $string);
+		}
+
+		return $string;
 	}
 
 	/**
@@ -289,6 +294,11 @@ public static function stripImages($string)
 	 */
 	public static function stripIframes($string)
 	{
-		return preg_replace('#(<[/]?iframe.*>)#U', '', $string);
+		while (preg_match('#(<[/]?iframe.*>)#Ui', $string))
+		{
+			$string = preg_replace('#(<[/]?iframe.*>)#Ui', '', $string);
+		}
+
+		return $string;
 	}
 }