--- a/image/DecoderFactory.cpp
+++ b/image/DecoderFactory.cpp
@@ -50,18 +50,16 @@ DecoderFactory::GetDecoderType(const cha
   } else if (!strcmp(aMimeType, IMAGE_PJPEG)) {
     type = DecoderType::JPEG;
   } else if (!strcmp(aMimeType, IMAGE_JPG)) {
     type = DecoderType::JPEG;
 
   // BMP
   } else if (!strcmp(aMimeType, IMAGE_BMP)) {
     type = DecoderType::BMP;
-  } else if (!strcmp(aMimeType, IMAGE_BMP_MS)) {
-    type = DecoderType::BMP;
 
   // ICO
   } else if (!strcmp(aMimeType, IMAGE_ICO)) {
     type = DecoderType::ICO;
   } else if (!strcmp(aMimeType, IMAGE_ICO_MS)) {
     type = DecoderType::ICO;
 
   // Icon

--- a/image/build/nsImageModule.cpp
+++ b/image/build/nsImageModule.cpp
@@ -72,17 +72,16 @@ static const mozilla::Module::ContractID
 static const mozilla::Module::CategoryEntry kImageCategories[] = {
   { "Gecko-Content-Viewers", IMAGE_GIF, "@mozilla.org/content/document-loader-factory;1" },
   { "Gecko-Content-Viewers", IMAGE_JPEG, "@mozilla.org/content/document-loader-factory;1" },
   { "Gecko-Content-Viewers", IMAGE_PJPEG, "@mozilla.org/content/document-loader-factory;1" },
   { "Gecko-Content-Viewers", IMAGE_JPG, "@mozilla.org/content/document-loader-factory;1" },
   { "Gecko-Content-Viewers", IMAGE_ICO, "@mozilla.org/content/document-loader-factory;1" },
   { "Gecko-Content-Viewers", IMAGE_ICO_MS, "@mozilla.org/content/document-loader-factory;1" },
   { "Gecko-Content-Viewers", IMAGE_BMP, "@mozilla.org/content/document-loader-factory;1" },
-  { "Gecko-Content-Viewers", IMAGE_BMP_MS, "@mozilla.org/content/document-loader-factory;1" },
   { "Gecko-Content-Viewers", IMAGE_ICON_MS, "@mozilla.org/content/document-loader-factory;1" },
   { "Gecko-Content-Viewers", IMAGE_PNG, "@mozilla.org/content/document-loader-factory;1" },
   { "Gecko-Content-Viewers", IMAGE_APNG, "@mozilla.org/content/document-loader-factory;1" },
   { "Gecko-Content-Viewers", IMAGE_X_PNG, "@mozilla.org/content/document-loader-factory;1" },
   { "content-sniffing-services", "@mozilla.org/image/loader;1", "@mozilla.org/image/loader;1" },
   { nullptr }
 };
 

--- a/netwerk/mime/nsMimeTypes.h
+++ b/netwerk/mime/nsMimeTypes.h
@@ -101,17 +101,16 @@
 #define IMAGE_X_PNG                         "image/x-png"
 #define IMAGE_PPM                           "image/x-portable-pixmap"
 #define IMAGE_XBM                           "image/x-xbitmap"
 #define IMAGE_XBM2                          "image/x-xbm"
 #define IMAGE_XBM3                          "image/xbm"
 #define IMAGE_ART                           "image/x-jg"
 #define IMAGE_TIFF                          "image/tiff"
 #define IMAGE_BMP                           "image/bmp"
-#define IMAGE_BMP_MS                        "image/x-ms-bmp"
 #define IMAGE_ICO                           "image/x-icon"
 #define IMAGE_ICO_MS                        "image/vnd.microsoft.icon"
 #define IMAGE_ICON_MS                       "image/icon"
 #define IMAGE_MNG                           "video/x-mng"
 #define IMAGE_JNG                           "image/x-jng"
 #define IMAGE_SVG_XML                       "image/svg+xml"
 
 #define MESSAGE_EXTERNAL_BODY               "message/external-body"