diff --git a/lcl/graphtype.pp b/lcl/graphtype.pp
index 820922ab4d..a05be26d45 100644
--- a/lcl/graphtype.pp
+++ b/lcl/graphtype.pp
@@ -319,7 +319,7 @@ begin
   if H < 0 then Exit;
   
   // calc destination rowstride
-  RS := (W * ABPP) shr 3;
+  RS := (W * ABPP + 7) shr 3;
   x := RS and SIZEMAP[ADestinationEnd];
   if x <> 0
   then Inc(RS, 1 + SIZEMAP[ADestinationEnd] - x);
diff --git a/lcl/interfaces/win32/win32wsimglist.pp b/lcl/interfaces/win32/win32wsimglist.pp
index 0f99e51a39..88fe3592d6 100644
--- a/lcl/interfaces/win32/win32wsimglist.pp
+++ b/lcl/interfaces/win32/win32wsimglist.pp
@@ -192,6 +192,9 @@ class procedure TWin32WSCustomImageList.AddData(AListHandle: TLCLIntfHandle; ACo
           else P^ := P^ shl 1;
           Inc(AData);
         end;
+        // finish mask shifting
+        if (AWidth and $7) <> 0 then
+          P^ := P^ shl (7 - (AWidth mod 8));
         Inc(LinePtr, MaskStride);
       end;