Rewrite screenshot saving.

OpenRA.Game/Game.cs

@@ -530,31 +530,19 @@ namespace OpenRA
 
 		static void TakeScreenshotInner()
 		{
-			Log.Write("debug", "Taking screenshot");
-
-			Bitmap bitmap;
-			using (new PerfTimer("Renderer.TakeScreenshot"))
-				bitmap = Renderer.Context.TakeScreenshot();
-
-			ThreadPool.QueueUserWorkItem(_ =>
+			using (new PerfTimer("Renderer.SaveScreenshot"))
 			{
 				var mod = ModData.Manifest.Metadata;
 				var directory = Platform.ResolvePath(Platform.SupportDirPrefix, "Screenshots", ModData.Manifest.Id, mod.Version);
 				Directory.CreateDirectory(directory);
 
 				var filename = TimestampedFilename(true);
-				var format = Settings.Graphics.ScreenshotFormat;
-				var extension = ImageCodecInfo.GetImageEncoders().FirstOrDefault(x => x.FormatID == format.Guid)
-					.FilenameExtension.Split(';').First().ToLowerInvariant().Substring(1);
-				var destination = Path.Combine(directory, string.Concat(filename, extension));
+				var path = Path.Combine(directory, string.Concat(filename, ".png"));
+				Log.Write("debug", "Taking screenshot " + path);
 
-				using (new PerfTimer("Save Screenshot ({0})".F(format)))
-					bitmap.Save(destination, format);
-
-				bitmap.Dispose();
-
-				RunAfterTick(() => Debug("Saved screenshot " + filename));
-			});
+				Renderer.Context.SaveScreenshot(path);
+				Debug("Saved screenshot " + filename);
+			}
 		}
 
 		static void InnerLogicTick(OrderManager orderManager)

OpenRA.Game/Graphics/PlatformInterfaces.cs

@@ -61,7 +61,7 @@ namespace OpenRA
 		IShader CreateShader(string name);
 		void EnableScissor(int left, int top, int width, int height);
 		void DisableScissor();
-		Bitmap TakeScreenshot();
+		void SaveScreenshot(string path);
 		void Present();
 		void DrawPrimitives(PrimitiveType pt, int firstVertex, int numVertices);
 		void Clear();

OpenRA.Game/Settings.cs

@@ -11,7 +11,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Drawing.Imaging;
 using System.IO;
 using System.Linq;
 using OpenRA.Graphics;
@@ -166,8 +165,6 @@ namespace OpenRA
 
 		public string Language = "english";
 		public string DefaultLanguage = "english";
-
-		public ImageFormat ScreenshotFormat = ImageFormat.Png;
 	}
 
 	public class SoundSettings