diff --git a/src/UglyToad.PdfPig.Tests/Integration/GithubIssuesTests.cs b/src/UglyToad.PdfPig.Tests/Integration/GithubIssuesTests.cs
index e3c41d41..c89a83f6 100644
--- a/src/UglyToad.PdfPig.Tests/Integration/GithubIssuesTests.cs
+++ b/src/UglyToad.PdfPig.Tests/Integration/GithubIssuesTests.cs
@@ -7,6 +7,24 @@
 
     public class GithubIssuesTests
     {
+        [Fact]
+        public void Issue1054()
+        {
+            var path = IntegrationHelpers.GetSpecificTestDocumentPath("MOZILLA-11518-0.pdf");
+
+            using (var document = PdfDocument.Open(path, new ParsingOptions() { UseLenientParsing = true }))
+            {
+                for (int p = 1; p <= document.NumberOfPages; p++)
+                {
+                    var page = document.GetPage(p);
+                    foreach (var image in page.GetImages())
+                    {
+                        Assert.NotNull(image);
+                    }
+                }
+            }
+        }
+
         [Fact]
         public void Issue1050()
         {
diff --git a/src/UglyToad.PdfPig.Tests/Integration/SpecificTestDocuments/MOZILLA-11518-0.pdf b/src/UglyToad.PdfPig.Tests/Integration/SpecificTestDocuments/MOZILLA-11518-0.pdf
new file mode 100644
index 00000000..a1eebc48
Binary files /dev/null and b/src/UglyToad.PdfPig.Tests/Integration/SpecificTestDocuments/MOZILLA-11518-0.pdf differ
diff --git a/src/UglyToad.PdfPig/XObjects/XObjectFactory.cs b/src/UglyToad.PdfPig/XObjects/XObjectFactory.cs
index 9892281c..6a319241 100644
--- a/src/UglyToad.PdfPig/XObjects/XObjectFactory.cs
+++ b/src/UglyToad.PdfPig/XObjects/XObjectFactory.cs
@@ -73,10 +73,16 @@
             }
             else if (dictionary.TryGet(NameToken.Mask, out StreamToken maskStream))
             {
-                if (maskStream.StreamDictionary.ContainsKey(NameToken.ColorSpace))
-                {
-                    throw new Exception("The SMask dictionary contains a 'ColorSpace'.");
-                }
+                /* As per Pdf Specifications:
+                 *  "The image dictionary shall not contain a ColorSpace entry because sample values represent masking properties (1 bit per sample) rather than colours."
+                 *
+                 * TODO - We assume here lenient parsing, but we should actually get the value from parsing options. See Issue #1054
+                 *
+                 * if (maskStream.StreamDictionary.ContainsKey(NameToken.ColorSpace))
+                 * {
+                 *      throw new Exception("The SMask dictionary contains a 'ColorSpace'.");
+                 * }
+                 */
 
                 // Stencil masking
                 XObjectContentRecord maskImageRecord = new XObjectContentRecord(XObjectType.Image,