diff --git a/src/main/java/com/iqser/red/pdftronlogic/commons/MarkedContentStack.java b/src/main/java/com/iqser/red/pdftronlogic/commons/MarkedContentStack.java
index 03bc969..21c7e22 100644
--- a/src/main/java/com/iqser/red/pdftronlogic/commons/MarkedContentStack.java
+++ b/src/main/java/com/iqser/red/pdftronlogic/commons/MarkedContentStack.java
@@ -3,12 +3,10 @@ package com.iqser.red.pdftronlogic.commons;
 import java.util.Deque;
 import java.util.Iterator;
 import java.util.LinkedList;
-import java.util.Optional;
 import java.util.Set;
 
 import com.pdftron.pdf.Element;
 import com.pdftron.pdf.PDFDoc;
-import com.pdftron.pdf.ocg.Group;
 import com.pdftron.sdf.Obj;
 
 import lombok.RequiredArgsConstructor;
diff --git a/src/main/java/com/iqser/red/pdftronlogic/commons/features/ElementFeatureFactory.java b/src/main/java/com/iqser/red/pdftronlogic/commons/features/ElementFeatureFactory.java
index 95d61b4..e97a2e0 100644
--- a/src/main/java/com/iqser/red/pdftronlogic/commons/features/ElementFeatureFactory.java
+++ b/src/main/java/com/iqser/red/pdftronlogic/commons/features/ElementFeatureFactory.java
@@ -15,6 +15,7 @@ import com.pdftron.pdf.Font;
 import com.pdftron.pdf.GState;
 import com.pdftron.pdf.Image;
 import com.pdftron.pdf.PathData;
+import com.pdftron.sdf.Obj;
 
 import lombok.SneakyThrows;
 import lombok.experimental.UtilityClass;
@@ -72,7 +73,7 @@ public class ElementFeatureFactory {
             boolean masked = false;
             if (element.getType() == Element.e_image) {
                 Image image = new Image(element.getXObject());
-                if (image.getMask() != null) {
+                if (image.getMask() != null && image.getMask().getType() == Obj.e_stream) {
                     Image imageMask = new Image(image.getMask());
                     masked = imageMask.isImageMask();
                 }