diff --git a/src/Http.hx b/src/Http.hx
index 9079a0f2..44295956 100644
--- a/src/Http.hx
+++ b/src/Http.hx
@@ -7,6 +7,8 @@ typedef HttpRequest = {
 	var url:String;
 	var callback:haxe.io.Bytes->Void;
 	var errCallback:String->Void;
+	var cancelled:Bool;
+	var fulfilled:Bool;
 };
 
 class Http {
@@ -14,6 +16,7 @@ class Http {
 	static var threadPool:sys.thread.FixedThreadPool;
 	static var requests:sys.thread.Deque<HttpRequest> = new sys.thread.Deque<HttpRequest>();
 	static var responses:sys.thread.Deque<() -> Void> = new sys.thread.Deque<() -> Void>();
+	static var cancellationMutex:sys.thread.Mutex = new sys.thread.Mutex();
 	#end
 
 	public static function init() {
@@ -30,12 +33,20 @@ class Http {
 	static function threadLoop() {
 		while (true) {
 			var req = requests.pop(true);
+			cancellationMutex.acquire();
+			if (req.cancelled) {
+				cancellationMutex.release();
+				continue;
+			}
+			cancellationMutex.release();
 			var http = new sys.Http(req.url);
 			http.onError = (e) -> {
 				responses.add(() -> req.errCallback(e));
+				req.fulfilled = true;
 			};
 			http.onBytes = (b) -> {
 				responses.add(() -> req.callback(b));
+				req.fulfilled = true;
 			};
 			hl.Gc.blocking(true); // Wtf is this shit
 			http.request(false);
@@ -44,14 +55,17 @@ class Http {
 	}
 	#end
 
-	public static function get(url:String, callback:haxe.io.Bytes->Void, errCallback:String->Void):Void {
+	public static function get(url:String, callback:haxe.io.Bytes->Void, errCallback:String->Void) {
 		var req = {
 			url: url,
 			callback: callback,
-			errCallback: errCallback
+			errCallback: errCallback,
+			cancelled: false,
+			fulfilled: false
 		};
 		#if sys
 		requests.add(req);
+		return req;
 		#else
 		js.Browser.window.fetch(url).then(r -> r.arrayBuffer().then(b -> callback(haxe.io.Bytes.ofData(b))), e -> errCallback(e.toString()));
 		#end
@@ -65,4 +79,12 @@ class Http {
 		}
 		#end
 	}
+
+	public static function cancel(req:HttpRequest) {
+		#if sys
+		cancellationMutex.acquire();
+		req.cancelled = true;
+		cancellationMutex.release();
+		#end
+	}
 }
diff --git a/src/Marbleland.hx b/src/Marbleland.hx
index a9465a38..0a15e59b 100644
--- a/src/Marbleland.hx
+++ b/src/Marbleland.hx
@@ -88,7 +88,7 @@ class Marbleland {
 	}
 
 	public static function getMissionImage(id:Int, cb:Image->Void) {
-		Http.get('https://marbleland.vani.ga/api/level/${id}/image?width=258&height=194', (imageBytes) -> {
+		return Http.get('https://marbleland.vani.ga/api/level/${id}/image?width=258&height=194', (imageBytes) -> {
 			var res = new Image(new hxd.fs.BytesFileSystem.BytesFileEntry('${id}.png', imageBytes));
 			cb(res);
 		}, (e) -> {
diff --git a/src/Mission.hx b/src/Mission.hx
index dd2c2a4f..1c59eec8 100644
--- a/src/Mission.hx
+++ b/src/Mission.hx
@@ -1,5 +1,6 @@
 package src;
 
+import src.Http.HttpRequest;
 import gui.Canvas;
 import gui.MessageBoxOkDlg;
 import haxe.Json;
@@ -19,6 +20,7 @@ import src.Util;
 import src.Console;
 import src.Marbleland;
 import src.MarbleGame;
+import src.Http;
 
 class Mission {
 	public var root:MissionElementSimGroup;
@@ -44,7 +46,7 @@ class Mission {
 
 	var imgFileEntry:hxd.fs.FileEntry;
 
-	static var doingLoadPreviewTimeout = false;
+	static var _previewRequest:HttpRequest;
 
 	public function new() {}
 
@@ -162,7 +164,10 @@ class Mission {
 			onLoaded(Tile.fromBitmap(img));
 			return null;
 		} else {
-			Marbleland.getMissionImage(this.id, (im) -> {
+			if (_previewRequest != null && !_previewRequest.fulfilled) {
+				Http.cancel(_previewRequest); // Cancel the previous request to save dequeing
+			}
+			_previewRequest = Marbleland.getMissionImage(this.id, (im) -> {
 				if (im != null) {
 					onLoaded(im.toTile());
 				} else {