Use JsonConverter

Jellyfin.Api/Controllers/LiveTvController.cs

@@ -662,11 +662,10 @@ namespace Jellyfin.Api.Controllers
                 }
             }
 
-            var imageTypes = RequestHelpers.GetImageTypes(body.EnableImageTypes);
             var dtoOptions = new DtoOptions()
                 .AddItemFields(body.Fields)
                 .AddClientFields(Request)
-                .AddAdditionalDtoOptions(body.EnableImages, body.EnableUserData, body.ImageTypeLimit, imageTypes);
+                .AddAdditionalDtoOptions(body.EnableImages, body.EnableUserData, body.ImageTypeLimit, body.EnableImageTypes);
             return await _liveTvManager.GetPrograms(query, dtoOptions, CancellationToken.None).ConfigureAwait(false);
         }
 

Jellyfin.Api/Models/LiveTvDtos/GetProgramsDto.cs

@@ -1,4 +1,8 @@
 using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Text.Json.Serialization;
+using MediaBrowser.Common.Json.Converters;
+using MediaBrowser.Model.Entities;
 
 namespace Jellyfin.Api.Models.LiveTvDtos
 {
@@ -137,7 +141,9 @@ namespace Jellyfin.Api.Models.LiveTvDtos
         /// Gets or sets the image types to include in the output.
         /// Optional.
         /// </summary>
-        public string? EnableImageTypes { get; set; }
+        [JsonConverter(typeof(JsonCommaDelimitedArrayConverterFactory))]
+        [SuppressMessage("Microsoft.Performance", "CA1819:ReturnArrays", MessageId = "EnableImageTypes", Justification = "Imported from ServiceStack")]
+        public ImageType[] EnableImageTypes { get; set; } = Array.Empty<ImageType>();
 
         /// <summary>
         /// Gets or sets include user data.