diff --git a/OpenRA.Game/Map/Map.cs b/OpenRA.Game/Map/Map.cs
index 782c7fdbf8..b61ed70706 100644
--- a/OpenRA.Game/Map/Map.cs
+++ b/OpenRA.Game/Map/Map.cs
@@ -12,6 +12,7 @@ using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Drawing;
+using System.Drawing.Imaging;
 using System.IO;
 using System.Linq;
 using System.Security.Cryptography;
@@ -391,8 +392,16 @@ 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.Clone(original.Bounds(), PixelFormat.Format32bppArgb);
+					original.Dispose();
+				}
+			}
 
 			PostInit();
 
diff --git a/OpenRA.Game/Map/MapPreview.cs b/OpenRA.Game/Map/MapPreview.cs
index fb843d1eaa..ab3bbd3402 100644
--- a/OpenRA.Game/Map/MapPreview.cs
+++ b/OpenRA.Game/Map/MapPreview.cs
@@ -13,6 +13,7 @@ using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics.CodeAnalysis;
 using System.Drawing;
+using System.Drawing.Imaging;
 using System.IO;
 using System.Linq;
 using System.Net;
@@ -155,6 +156,12 @@ namespace OpenRA
 						SpawnPoints = spawns;
 
 						CustomPreview = new Bitmap(new MemoryStream(Convert.FromBase64String(r.minimap)));
+						if (CustomPreview.PixelFormat != PixelFormat.Format32bppArgb)
+						{
+							var original = CustomPreview;
+							CustomPreview = original.Clone(original.Bounds(), PixelFormat.Format32bppArgb);
+							original.Dispose();
+						}
 					}
 					catch (Exception) { }