diff --git a/basis/images/loader/gdiplus/gdiplus.factor b/basis/images/loader/gdiplus/gdiplus.factor
index 26dab0d58d..0eceef4a26 100644
--- a/basis/images/loader/gdiplus/gdiplus.factor
+++ b/basis/images/loader/gdiplus/gdiplus.factor
@@ -1,11 +1,13 @@
 ! (c)2010 Joe Groff bsd license
-USING: accessors alien.c-types alien.data alien.enums
-classes.struct destructors images images.loader kernel locals
-math windows.com windows.gdiplus windows.streams windows.types
-typed byte-arrays grouping sequences ;
+USING: accessors alien alien.c-types alien.data alien.enums alien.strings
+assocs byte-arrays classes.struct destructors grouping images images.loader
+io kernel locals math mime.types namespaces sequences specialized-arrays
+windows.com windows.gdiplus windows.streams windows.types ;
 FROM: system => os windows? ;
 IN: images.loader.gdiplus
 
+SPECIALIZED-ARRAY: ImageCodecInfo
+
 SINGLETON: gdi+-image
 
 os windows? [
@@ -14,6 +16,7 @@ os windows? [
 ] when
 
 <PRIVATE
+
 : <GpRect> ( x y w h -- rect )
     GpRect <struct-boa> ; inline
 
@@ -25,9 +28,11 @@ os windows? [
 : gdi+-bitmap-width ( bitmap -- w )
     { UINT } [ GdipGetImageWidth check-gdi+-status ]
     with-out-parameters ;
-: gdi+-bitmap-height ( bitmap -- w )
+
+: gdi+-bitmap-height ( bitmap -- h )
     { UINT } [ GdipGetImageHeight check-gdi+-status ]
     with-out-parameters ;
+
 : gdi+-lock-bitmap ( bitmap rect mode format -- data )
     { BitmapData } [ GdipBitmapLockBits check-gdi+-status ]
     with-out-parameters ;
@@ -40,7 +45,7 @@ os windows? [
     memory>byte-array :> pixels
     bitmap bitmap-data GdipBitmapUnlockBits check-gdi+-status
     w h pixels ;
-    
+
 :: data>image ( w h pixels -- image )
     image new
         { w h } >>dim
@@ -49,11 +54,53 @@ os windows? [
         ubyte-components >>component-type
         f >>upside-down? ;
 
+! Only one pixel format supported, but I can't find images in the
+! wild, loaded using gdi+, in which the format is different.
+ERROR: unsupported-pixel-format component-order ;
+
+: check-pixel-format ( image -- )
+    component-order>> dup BGRA = [ drop ] [ unsupported-pixel-format ] if ;
+
+: image>gdi+-bitmap ( image -- bitmap )
+    dup check-pixel-format
+    [ dim>> first2 ] [ rowstride PixelFormat32bppARGB ] [ bitmap>> ] tri
+    { void* } [
+        GdipCreateBitmapFromScan0 check-gdi+-status
+    ] with-out-parameters &GdipFree ;
+
+: image-encoders-size ( -- num size )
+    { UINT UINT } [
+        GdipGetImageEncodersSize check-gdi+-status
+    ] with-out-parameters ;
+
+: image-encoders ( -- codec-infos )
+    image-encoders-size dup <byte-array> 3dup
+    GdipGetImageEncoders check-gdi+-status
+    nip swap <direct-ImageCodecInfo-array> ;
+
+: extension>mime-type ( extension -- mime-type )
+    ! Crashes if you let this mime through on my machine.
+    dup mime-types at dup "image/bmp" = [ unknown-image-extension ] when nip ;
+
+: mime-type>clsid ( mime-type -- clsid )
+    image-encoders [ MimeType>> alien>native-string = ] with find nip Clsid>> ;
+
+: startup-gdi+ ( -- )
+    start-gdi+ &stop-gdi+ drop ;
+
+: write-image-to-stream ( image stream extension -- )
+    [ image>gdi+-bitmap ]
+    [ stream>IStream &com-release ]
+    [ extension>mime-type mime-type>clsid ] tri*
+    f GdipSaveImageToStream check-gdi+-status ;
+
 PRIVATE>
 
 M: gdi+-image stream>image*
-    drop
-    start-gdi+ &stop-gdi+ drop
+    drop startup-gdi+
     stream>gdi+-bitmap
     gdi+-bitmap>data
     data>image ;
+
+M: gdi+-image image>stream ( image extension class -- )
+    drop startup-gdi+ output-stream get swap write-image-to-stream ;
diff --git a/basis/images/loader/loader-tests.factor b/basis/images/loader/loader-tests.factor
index 54de95e9a6..4a3c045d81 100644
--- a/basis/images/loader/loader-tests.factor
+++ b/basis/images/loader/loader-tests.factor
@@ -1,16 +1,42 @@
-USING: continuations images.loader io.files.temp kernel system tools.test ;
+USING: continuations images.loader io.files.temp kernel sequences system
+tools.test ;
 IN: images.loader.tests
 
-os linux? [
-    [ t ] [
-        "vocab:images/testing/png/basi0g01.png" load-image dup
-        "foo.bmp" temp-file [ save-graphic-image ] [ load-image ] bi =
+CONSTANT: basi0g01.png "vocab:images/testing/png/basi0g01.png"
+
+os { linux windows } member? [
+
+    { { t t t } } [
+        basi0g01.png load-image dup
+        { "png" "gif" "tif" } [
+            "foo." prepend temp-file [ save-graphic-image ] keep
+        ] with map
+        [ load-image = ] with map
     ] unit-test
 
-    [ t ] [
+    { t } [
         [
-            "vocab:images/testing/png/basi0g01.png" load-image
+            basi0g01.png load-image
             "hai!" save-graphic-image
         ] [ unknown-image-extension? ] recover
     ] unit-test
+
+    ! Windows can't save .bmp-files for unknown reason. It can load
+    ! them though.
+    os windows? [
+        [
+            basi0g01.png load-image "foo.bmp" temp-file save-graphic-image
+        ] [ unknown-image-extension? ] must-fail-with
+    ] [
+        { t } [
+            basi0g01.png load-image dup
+            "foo.bmp" temp-file [ save-graphic-image ] [ load-image ] bi =
+        ] unit-test
+    ] if
+
+    { t } [
+        "vocab:images/testing/bmp/rgb_8bit.bmp" load-image dup
+        "foo.png" temp-file [ save-graphic-image ] [ load-image ] bi =
+    ] unit-test
+
 ] when