UI now loads the 250px image if available, and reverts to full size otherwise.

src/NzbDrone.Api/Frontend/Mappers/MediaCoverMapper.cs

@@ -1,4 +1,6 @@
 using System.IO;
+using System.Text.RegularExpressions;
+using Nancy;
 using NLog;
 using NzbDrone.Common.Disk;
 using NzbDrone.Common.EnvironmentInfo;
@@ -8,6 +10,8 @@ namespace NzbDrone.Api.Frontend.Mappers
 {
     public class MediaCoverMapper : StaticResourceMapperBase
     {
+        private static readonly Regex RegexResizedImage = new Regex(@"-\d+\.jpg($|\?)", RegexOptions.Compiled | RegexOptions.IgnoreCase);
+
         private readonly IAppFolderInfo _appFolderInfo;
 
         public MediaCoverMapper(IAppFolderInfo appFolderInfo, IDiskProvider diskProvider, Logger logger)
@@ -24,6 +28,24 @@ namespace NzbDrone.Api.Frontend.Mappers
             return Path.Combine(_appFolderInfo.GetAppDataPath(), path);
         }
 
+        public override Response GetResponse(string resourceUrl)
+        {
+            var result =  base.GetResponse(resourceUrl);
+
+            // Return the full sized image if someone requests a non-existing resized one.
+            // TODO: This code can be removed later once everyone had the update for a while.
+            if (result is NotFoundResponse)
+            {
+                var baseResourceUrl = RegexResizedImage.Replace(resourceUrl, ".jpg$1");
+                if (baseResourceUrl != resourceUrl)
+                {
+                    result = base.GetResponse(baseResourceUrl);
+                }
+            }
+
+            return result;
+        }
+
         public override bool CanHandle(string resourceUrl)
         {
             return resourceUrl.StartsWith("/MediaCover");