Add fallback for image downloads with bad MediaType

MediaBrowser.Providers/Manager/ProviderManager.cs

@@ -30,6 +30,7 @@ using MediaBrowser.Model.Configuration;
 using MediaBrowser.Model.Entities;
 using MediaBrowser.Model.Extensions;
 using MediaBrowser.Model.IO;
+using MediaBrowser.Model.Net;
 using MediaBrowser.Model.Providers;
 using Microsoft.Extensions.Logging;
 using Priority_Queue;
@@ -188,6 +189,12 @@ namespace MediaBrowser.Providers.Manager
                 throw new HttpRequestException("Invalid image received.", null, HttpStatusCode.NotFound);
             }
 
+            // some iptv/epg providers don't correctly report media type, extract from url if no extension found
+            if (string.IsNullOrWhiteSpace(MimeTypes.ToExtension(contentType)))
+            {
+                contentType = MimeTypes.GetMimeType(url);
+            }
+
             await using var stream = await response.Content.ReadAsStreamAsync(cancellationToken).ConfigureAwait(false);
             await SaveImage(
                 item,