--- a/OrthancServer/Sources/OrthancRestApi/OrthancRestResources.cpp	Mon Aug 30 22:21:24 2021 +0200
+++ b/OrthancServer/Sources/OrthancRestApi/OrthancRestResources.cpp	Thu Nov 25 13:12:32 2021 +0100
@@ -743,6 +743,7 @@
             .SetTag("Instances")
             .SetUriArgument("id", "Orthanc identifier of the DICOM instance of interest")
             .SetHttpGetArgument("quality", RestApiCallDocumentation::Type_Number, "Quality for JPEG images (between 1 and 100, defaults to 90)", false)
+            .SetHttpGetArgument("returnUnsupportedImage", RestApiCallDocumentation::Type_Boolean, "Returns an unsupported.png placeholder image if unable to provide the image instead of returning a 415 HTTP error (defaults to false)", false)
             .SetHttpHeader("Accept", "Format of the resulting image. Can be `image/png` (default), `image/jpeg` or `image/x-portable-arbitrarymap`")
             .AddAnswerType(MimeType_Png, "PNG image")
             .AddAnswerType(MimeType_Jpeg, "JPEG image")
@@ -805,13 +806,20 @@
           }
           else
           {
-            std::string root = "";
-            for (size_t i = 1; i < call.GetFullUri().size(); i++)
+            if (call.HasArgument("returnUnsupportedImage"))
             {
-              root += "../";
+              std::string root = "";
+              for (size_t i = 1; i < call.GetFullUri().size(); i++)
+              {
+                root += "../";
+              }
+
+              call.GetOutput().Redirect(root + "app/images/unsupported.png");
             }
-
-            call.GetOutput().Redirect(root + "app/images/unsupported.png");
+            else
+            {
+              call.GetOutput().SignalError(HttpStatus_415_UnsupportedMediaType);
+            }
           }
           return;
         }
@@ -2957,7 +2965,7 @@
     std::string publicId = call.GetUriComponent("id", "");
 
     std::string dicomContent;
-    context.ReadDicom(dicomContent, publicId);
+    context.ReadDicomForHeader(dicomContent, publicId);
 
     // TODO Consider using "DicomMap::ParseDicomMetaInformation()" to
     // speed up things here