diff --git a/back/src/Kyoo.Abstractions/Controllers/ILibraryManager.cs b/back/src/Kyoo.Abstractions/Controllers/ILibraryManager.cs
index cc3e2f5b..e1a2f299 100644
--- a/back/src/Kyoo.Abstractions/Controllers/ILibraryManager.cs
+++ b/back/src/Kyoo.Abstractions/Controllers/ILibraryManager.cs
@@ -26,7 +26,7 @@ namespace Kyoo.Abstractions.Controllers
 	public interface ILibraryManager
 	{
 		IRepository<T> Repository<T>()
-			where T : class, IResource, IQuery;
+			where T : IResource, IQuery;
 
 		/// <summary>
 		/// The repository that handle libraries items (a wrapper around shows and collections).
diff --git a/back/src/Kyoo.Abstractions/Controllers/IRepository.cs b/back/src/Kyoo.Abstractions/Controllers/IRepository.cs
index 85161a55..b53d8c38 100644
--- a/back/src/Kyoo.Abstractions/Controllers/IRepository.cs
+++ b/back/src/Kyoo.Abstractions/Controllers/IRepository.cs
@@ -30,7 +30,7 @@ namespace Kyoo.Abstractions.Controllers
 	/// </summary>
 	/// <typeparam name="T">The resource's type that this repository manage.</typeparam>
 	public interface IRepository<T> : IBaseRepository
-		where T : class, IResource, IQuery
+		where T : IResource, IQuery
 	{
 		/// <summary>
 		/// The event handler type for all events of this repository.
diff --git a/back/src/Kyoo.Abstractions/Controllers/IThumbnailsManager.cs b/back/src/Kyoo.Abstractions/Controllers/IThumbnailsManager.cs
index 8ef426c5..810998d8 100644
--- a/back/src/Kyoo.Abstractions/Controllers/IThumbnailsManager.cs
+++ b/back/src/Kyoo.Abstractions/Controllers/IThumbnailsManager.cs
@@ -36,7 +36,7 @@ namespace Kyoo.Abstractions.Controllers
 		/// The item to cache images.
 		/// </param>
 		/// <typeparam name="T">The type of the item</typeparam>
-		/// <returns><c>true</c> if an image has been downloaded, <c>false</c> otherwise.</returns>
+		/// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
 		Task DownloadImages<T>(T item)
 			where T : IThumbnails;
 
@@ -50,5 +50,16 @@ namespace Kyoo.Abstractions.Controllers
 		/// <returns>The path of the image for the given resource or null if it does not exists.</returns>
 		string GetImagePath<T>(T item, string image, ImageQuality quality)
 			where T : IThumbnails;
+
+		/// <summary>
+		/// Delete images associated with the item.
+		/// </summary>
+		/// <param name="item">
+		/// The item with cached images.
+		/// </param>
+		/// <typeparam name="T">The type of the item</typeparam>
+		/// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
+		Task DeleteImages<T>(T item)
+			where T : IThumbnails;
 	}
 }
diff --git a/back/src/Kyoo.Abstractions/Models/Resources/Interfaces/IResource.cs b/back/src/Kyoo.Abstractions/Models/Resources/Interfaces/IResource.cs
index b7a7f4b6..2356965e 100644
--- a/back/src/Kyoo.Abstractions/Models/Resources/Interfaces/IResource.cs
+++ b/back/src/Kyoo.Abstractions/Models/Resources/Interfaces/IResource.cs
@@ -25,7 +25,7 @@ namespace Kyoo.Abstractions.Models
 	/// <summary>
 	/// An interface to represent a resource that can be retrieved from the database.
 	/// </summary>
-	public interface IResource
+	public interface IResource : IQuery
 	{
 		/// <summary>
 		/// A unique ID for this type of resource. This can't be changed and duplicates are not allowed.
diff --git a/back/src/Kyoo.Core/Controllers/LibraryManager.cs b/back/src/Kyoo.Core/Controllers/LibraryManager.cs
index c9bc1b48..f9a1565f 100644
--- a/back/src/Kyoo.Core/Controllers/LibraryManager.cs
+++ b/back/src/Kyoo.Core/Controllers/LibraryManager.cs
@@ -92,7 +92,7 @@ namespace Kyoo.Core.Controllers
 		public IRepository<User> Users { get; }
 
 		public IRepository<T> Repository<T>()
-			where T : class, IResource, IQuery
+			where T : IResource, IQuery
 		{
 			return (IRepository<T>)_repositories.First(x => x.RepositoryType == typeof(T));
 		}
diff --git a/back/src/Kyoo.Core/Controllers/Repositories/EpisodeRepository.cs b/back/src/Kyoo.Core/Controllers/Repositories/EpisodeRepository.cs
index 0f6bd9ea..c3b98c33 100644
--- a/back/src/Kyoo.Core/Controllers/Repositories/EpisodeRepository.cs
+++ b/back/src/Kyoo.Core/Controllers/Repositories/EpisodeRepository.cs
@@ -84,16 +84,20 @@ namespace Kyoo.Core.Controllers
 				.ToListAsync();
 		}
 
+		protected override Task<Episode?> GetDuplicated(Episode item)
+		{
+			if (item is { SeasonNumber: not null, EpisodeNumber: not null })
+				return _database.Episodes.FirstOrDefaultAsync(x => x.ShowId == item.ShowId && x.SeasonNumber == item.SeasonNumber && x.EpisodeNumber == item.EpisodeNumber);
+			return _database.Episodes.FirstOrDefaultAsync(x => x.ShowId == item.ShowId && x.AbsoluteNumber == item.AbsoluteNumber);
+		}
+
 		/// <inheritdoc />
 		public override async Task<Episode> Create(Episode obj)
 		{
 			obj.ShowSlug = obj.Show?.Slug ?? (await _database.Shows.FirstAsync(x => x.Id == obj.ShowId)).Slug;
 			await base.Create(obj);
 			_database.Entry(obj).State = EntityState.Added;
-			await _database.SaveChangesAsync(() =>
-				obj is { SeasonNumber: not null, EpisodeNumber: not null }
-				? _database.Episodes.FirstOrDefaultAsync(x => x.ShowId == obj.ShowId && x.SeasonNumber == obj.SeasonNumber && x.EpisodeNumber == obj.EpisodeNumber)
-				: _database.Episodes.FirstOrDefaultAsync(x => x.ShowId == obj.ShowId && x.AbsoluteNumber == obj.AbsoluteNumber));
+			await _database.SaveChangesAsync(() => GetDuplicated(obj));
 			await IRepository<Episode>.OnResourceCreated(obj);
 			return obj;
 		}
diff --git a/back/src/Kyoo.Core/Controllers/Repositories/LocalRepository.cs b/back/src/Kyoo.Core/Controllers/Repositories/LocalRepository.cs
index 4a8d60d3..64b76b5c 100644
--- a/back/src/Kyoo.Core/Controllers/Repositories/LocalRepository.cs
+++ b/back/src/Kyoo.Core/Controllers/Repositories/LocalRepository.cs
@@ -214,6 +214,11 @@ namespace Kyoo.Core.Controllers
 			return ret;
 		}
 
+		protected virtual Task<T?> GetDuplicated(T item)
+		{
+			return GetOrDefault(item.Slug);
+		}
+
 		/// <inheritdoc />
 		public virtual Task<T?> GetOrDefault(Guid id, Include<T>? include = default)
 		{
@@ -324,7 +329,14 @@ namespace Kyoo.Core.Controllers
 			await Validate(obj);
 			if (obj is IThumbnails thumbs)
 			{
-				await _thumbs.DownloadImages(thumbs);
+				try
+				{
+					await _thumbs.DownloadImages(thumbs);
+				}
+				catch (DuplicatedItemException e) when (e.Existing is null)
+				{
+					throw new DuplicatedItemException(await GetDuplicated(obj));
+				}
 				if (thumbs.Poster != null)
 					Database.Entry(thumbs).Reference(x => x.Poster).TargetEntry!.State = EntityState.Added;
 				if (thumbs.Thumbnail != null)
@@ -470,6 +482,8 @@ namespace Kyoo.Core.Controllers
 		public virtual Task Delete(T obj)
 		{
 			IRepository<T>.OnResourceDeleted(obj);
+			if (obj is IThumbnails thumbs)
+				return _thumbs.DeleteImages(thumbs);
 			return Task.CompletedTask;
 		}
 
diff --git a/back/src/Kyoo.Core/Controllers/Repositories/SeasonRepository.cs b/back/src/Kyoo.Core/Controllers/Repositories/SeasonRepository.cs
index 2ec418f8..19cd6e82 100644
--- a/back/src/Kyoo.Core/Controllers/Repositories/SeasonRepository.cs
+++ b/back/src/Kyoo.Core/Controllers/Repositories/SeasonRepository.cs
@@ -16,12 +16,13 @@
 // You should have received a copy of the GNU General Public License
 // along with Kyoo. If not, see <https://www.gnu.org/licenses/>.
 
-using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
 using System.Linq;
 using System.Threading.Tasks;
 using Kyoo.Abstractions.Controllers;
 using Kyoo.Abstractions.Models;
+using Kyoo.Abstractions.Models.Exceptions;
 using Kyoo.Abstractions.Models.Utils;
 using Kyoo.Postgresql;
 using Microsoft.EntityFrameworkCore;
@@ -70,6 +71,11 @@ namespace Kyoo.Core.Controllers
 			_database = database;
 		}
 
+		protected override Task<Season?> GetDuplicated(Season item)
+		{
+			return _database.Seasons.FirstOrDefaultAsync(x => x.ShowId == item.ShowId && x.SeasonNumber == item.SeasonNumber);
+		}
+
 		/// <inheritdoc/>
 		public override async Task<ICollection<Season>> Search(string query, Include<Season>? include = default)
 		{
@@ -83,11 +89,10 @@ namespace Kyoo.Core.Controllers
 		public override async Task<Season> Create(Season obj)
 		{
 			await base.Create(obj);
-			obj.ShowSlug = _database.Shows.First(x => x.Id == obj.ShowId).Slug;
+			obj.ShowSlug = (await _database.Shows.FirstOrDefaultAsync(x => x.Id == obj.ShowId))?.Slug
+				?? throw new ItemNotFoundException($"No show found with ID {obj.ShowId}");
 			_database.Entry(obj).State = EntityState.Added;
-			await _database.SaveChangesAsync(() =>
-				_database.Seasons.FirstOrDefaultAsync(x => x.ShowId == obj.ShowId && x.SeasonNumber == obj.SeasonNumber)
-			);
+			await _database.SaveChangesAsync(() => GetDuplicated(obj));
 			await IRepository<Season>.OnResourceCreated(obj);
 			return obj;
 		}
@@ -100,7 +105,7 @@ namespace Kyoo.Core.Controllers
 			{
 				if (resource.Show == null)
 				{
-					throw new ArgumentException($"Can't store a season not related to any show " +
+					throw new ValidationException($"Can't store a season not related to any show " +
 						$"(showID: {resource.ShowId}).");
 				}
 				resource.ShowId = resource.Show.Id;
diff --git a/back/src/Kyoo.Core/Controllers/ThumbnailsManager.cs b/back/src/Kyoo.Core/Controllers/ThumbnailsManager.cs
index 6e4720ce..8e7339de 100644
--- a/back/src/Kyoo.Core/Controllers/ThumbnailsManager.cs
+++ b/back/src/Kyoo.Core/Controllers/ThumbnailsManager.cs
@@ -19,6 +19,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Net.Http;
 using System.Threading.Tasks;
 using Blurhash.SkiaSharp;
@@ -167,5 +168,24 @@ namespace Kyoo.Core.Controllers
 		{
 			return $"{_GetBaseImagePath(item, image)}.{quality.ToString().ToLowerInvariant()}.webp";
 		}
+
+		/// <inheritdoc />
+		public Task DeleteImages<T>(T item)
+			where T : IThumbnails
+		{
+			IEnumerable<string> images = new[] { "poster", "thumbnail", "logo" }
+				.SelectMany(x => _GetBaseImagePath(item, x))
+				.SelectMany(x => new[]
+					{
+						ImageQuality.High.ToString().ToLowerInvariant(),
+						ImageQuality.Medium.ToString().ToLowerInvariant(),
+						ImageQuality.Low.ToString().ToLowerInvariant(),
+					}.Select(quality => $"{x}.{quality}.webp")
+				);
+
+			foreach (string image in images)
+				File.Delete(image);
+			return Task.CompletedTask;
+		}
 	}
 }
diff --git a/back/src/Kyoo.Core/ExceptionFilter.cs b/back/src/Kyoo.Core/ExceptionFilter.cs
index 372f9564..9a5bdb28 100644
--- a/back/src/Kyoo.Core/ExceptionFilter.cs
+++ b/back/src/Kyoo.Core/ExceptionFilter.cs
@@ -54,9 +54,13 @@ namespace Kyoo.Core
 				case ItemNotFoundException ex:
 					context.Result = new NotFoundObjectResult(new RequestError(ex.Message));
 					break;
-				case DuplicatedItemException ex:
+				case DuplicatedItemException ex when ex.Existing is not null:
 					context.Result = new ConflictObjectResult(ex.Existing);
 					break;
+				case DuplicatedItemException:
+					// Should not happen but if it does, it is better than returning a 409 with no body since clients expect json content
+					context.Result = new ConflictObjectResult(new RequestError("Duplicated item"));
+					break;
 				case Exception ex:
 					_logger.LogError(ex, "Unhandled error");
 					context.Result = new ServerErrorObjectResult(new RequestError("Internal Server Error"));