diff --git a/OpenRA.Game/Graphics/Util.cs b/OpenRA.Game/Graphics/Util.cs
index 9851fcff52..e64c452e80 100644
--- a/OpenRA.Game/Graphics/Util.cs
+++ b/OpenRA.Game/Graphics/Util.cs
@@ -64,21 +64,33 @@ namespace OpenRA.Graphics
 
 		public static void FastCopyIntoSprite(Sprite dest, Bitmap src)
 		{
+			var createdTempBitmap = false;
 			if (src.PixelFormat != PixelFormat.Format32bppArgb)
-				throw new ArgumentException("src must have a PixelFormat of Format32bppArgb", "src");
+			{
+				src = src.CloneWith32bbpArgbPixelFormat();
+				createdTempBitmap = true;
+			}
 
-			var data = dest.Sheet.GetData();
-			var dataStride = dest.Sheet.Size.Width * 4;
-			var x = dest.Bounds.Left * 4;
-			var width = dest.Bounds.Width * 4;
-			var y = dest.Bounds.Top;
-			var height = dest.Bounds.Height;
+			try
+			{
+				var data = dest.Sheet.GetData();
+				var dataStride = dest.Sheet.Size.Width * 4;
+				var x = dest.Bounds.Left * 4;
+				var width = dest.Bounds.Width * 4;
+				var y = dest.Bounds.Top;
+				var height = dest.Bounds.Height;
 
-			var bd = src.LockBits(src.Bounds(),
-				ImageLockMode.ReadWrite, src.PixelFormat);
-			for (var row = 0; row < height; row++)
-				Marshal.Copy(IntPtr.Add(bd.Scan0, row * bd.Stride), data, (y + row) * dataStride + x, width);
-			src.UnlockBits(bd);
+				var bd = src.LockBits(src.Bounds(),
+					ImageLockMode.ReadWrite, src.PixelFormat);
+				for (var row = 0; row < height; row++)
+					Marshal.Copy(IntPtr.Add(bd.Scan0, row * bd.Stride), data, (y + row) * dataStride + x, width);
+				src.UnlockBits(bd);
+			}
+			finally
+			{
+				if (createdTempBitmap)
+					src.Dispose();
+			}
 		}
 
 		public static float[] IdentityMatrix()
diff --git a/OpenRA.Game/Map/Map.cs b/OpenRA.Game/Map/Map.cs
index ffbcf494ba..21231eb144 100644
--- a/OpenRA.Game/Map/Map.cs
+++ b/OpenRA.Game/Map/Map.cs
@@ -392,16 +392,8 @@ namespace OpenRA
 			DefaultSubCell = (SubCell)Game.ModData.Manifest.SubCellDefaultIndex;
 
 			if (Container.Exists("map.png"))
-			{
 				using (var dataStream = Container.GetContent("map.png"))
 					CustomPreview = new Bitmap(dataStream);
-				if (CustomPreview.PixelFormat != PixelFormat.Format32bppArgb)
-				{
-					var original = CustomPreview;
-					CustomPreview = original.CloneWith32bbpArgbPixelFormat();
-					original.Dispose();
-				}
-			}
 
 			PostInit();
 
diff --git a/OpenRA.Game/Map/MapPreview.cs b/OpenRA.Game/Map/MapPreview.cs
index 2b85004f38..783de198f6 100644
--- a/OpenRA.Game/Map/MapPreview.cs
+++ b/OpenRA.Game/Map/MapPreview.cs
@@ -156,12 +156,6 @@ namespace OpenRA
 						SpawnPoints = spawns;
 
 						CustomPreview = new Bitmap(new MemoryStream(Convert.FromBase64String(r.minimap)));
-						if (CustomPreview.PixelFormat != PixelFormat.Format32bppArgb)
-						{
-							var original = CustomPreview;
-							CustomPreview = original.CloneWith32bbpArgbPixelFormat();
-							original.Dispose();
-						}
 					}
 					catch (Exception) { }