diff --git a/src/Discord.Net.Core/CDN.cs b/src/Discord.Net.Core/CDN.cs
index c5f05c0c3..d3ade3722 100644
--- a/src/Discord.Net.Core/CDN.cs
+++ b/src/Discord.Net.Core/CDN.cs
@@ -1,16 +1,17 @@
-namespace Discord
+using System;
+
+namespace Discord
 {
     public static class CDN
     {
         public static string GetApplicationIconUrl(ulong appId, string iconId)
             => iconId != null ? $"{DiscordConfig.CDNUrl}app-icons/{appId}/{iconId}.jpg" : null;
-        public static string GetUserAvatarUrl(ulong userId, string avatarId, ushort size, AvatarFormat format)
+        public static string GetUserAvatarUrl(ulong userId, string avatarId, ushort size, ImageFormat format)
         {
             if (avatarId == null)
                 return null;
-            if (format == AvatarFormat.Auto)
-                format = avatarId.StartsWith("a_") ? AvatarFormat.Gif : AvatarFormat.Png;
-            return $"{DiscordConfig.CDNUrl}avatars/{userId}/{avatarId}.{format.ToString().ToLower()}?size={size}";
+            string extension = FormatToExtension(format, avatarId);
+            return $"{DiscordConfig.CDNUrl}avatars/{userId}/{avatarId}.{extension}?size={size}";
         }
         public static string GetGuildIconUrl(ulong guildId, string iconId)
             => iconId != null ? $"{DiscordConfig.CDNUrl}icons/{guildId}/{iconId}.jpg" : null;
@@ -20,5 +21,19 @@
             => iconId != null ? $"{DiscordConfig.CDNUrl}channel-icons/{channelId}/{iconId}.jpg" : null;
         public static string GetEmojiUrl(ulong emojiId)
             => $"{DiscordConfig.CDNUrl}emojis/{emojiId}.png";
+
+        private static string FormatToExtension(ImageFormat format, string imageId)
+        {
+            if (format == ImageFormat.Auto)
+                format = imageId.StartsWith("a_") ? ImageFormat.Gif : ImageFormat.Png;
+            switch (format)
+            {
+                case ImageFormat.Gif: return "gif";
+                case ImageFormat.Jpeg: return "jpeg";
+                case ImageFormat.Png: return "png";
+                case ImageFormat.WebP: return "webp";
+                default: throw new ArgumentException(nameof(format));
+            }
+        }
     }
 }
diff --git a/src/Discord.Net.Core/Entities/Users/AvatarFormat.cs b/src/Discord.Net.Core/Entities/ImageFormat.cs
similarity index 78%
rename from src/Discord.Net.Core/Entities/Users/AvatarFormat.cs
rename to src/Discord.Net.Core/Entities/ImageFormat.cs
index ef9e4b375..302da79c8 100644
--- a/src/Discord.Net.Core/Entities/Users/AvatarFormat.cs
+++ b/src/Discord.Net.Core/Entities/ImageFormat.cs
@@ -1,6 +1,6 @@
 namespace Discord
 {
-    public enum AvatarFormat
+    public enum ImageFormat
     {
         Auto,
         WebP,
diff --git a/src/Discord.Net.Core/Entities/Users/IUser.cs b/src/Discord.Net.Core/Entities/Users/IUser.cs
index 4d36295f3..62060da22 100644
--- a/src/Discord.Net.Core/Entities/Users/IUser.cs
+++ b/src/Discord.Net.Core/Entities/Users/IUser.cs
@@ -7,7 +7,7 @@ namespace Discord
         /// <summary> Gets the id of this user's avatar. </summary>
         string AvatarId { get; }
         /// <summary> Gets the url to this user's avatar. </summary>
-        string GetAvatarUrl(AvatarFormat format = AvatarFormat.Auto, ushort size = 128);
+        string GetAvatarUrl(ImageFormat format = ImageFormat.Auto, ushort size = 128);
         /// <summary> Gets the per-username unique id for this user. </summary>
         string Discriminator { get; }
         /// <summary> Gets the per-username unique id for this user. </summary>
diff --git a/src/Discord.Net.Rest/Entities/Users/RestUser.cs b/src/Discord.Net.Rest/Entities/Users/RestUser.cs
index 4d7ab5d15..0acfe3ddf 100644
--- a/src/Discord.Net.Rest/Entities/Users/RestUser.cs
+++ b/src/Discord.Net.Rest/Entities/Users/RestUser.cs
@@ -13,7 +13,8 @@ namespace Discord.Rest
         public ushort DiscriminatorValue { get; private set; }
         public string AvatarId { get; private set; }
 
-        public string GetAvatarUrl(AvatarFormat format = AvatarFormat.Auto, ushort size = 128) => CDN.GetUserAvatarUrl(Id, AvatarId, size, format);
+        public string GetAvatarUrl(ImageFormat format = ImageFormat.Auto, ushort size = 128) 
+            => CDN.GetUserAvatarUrl(Id, AvatarId, size, format);
         public DateTimeOffset CreatedAt => DateTimeUtils.FromSnowflake(Id);
         public string Discriminator => DiscriminatorValue.ToString("D4");
         public string Mention => MentionUtils.MentionUser(Id);
diff --git a/src/Discord.Net.Rpc/Entities/Users/RpcUser.cs b/src/Discord.Net.Rpc/Entities/Users/RpcUser.cs
index 24c715491..daf299e2a 100644
--- a/src/Discord.Net.Rpc/Entities/Users/RpcUser.cs
+++ b/src/Discord.Net.Rpc/Entities/Users/RpcUser.cs
@@ -14,7 +14,8 @@ namespace Discord.Rpc
         public ushort DiscriminatorValue { get; private set; }
         public string AvatarId { get; private set; }
 
-        public string GetAvatarUrl(AvatarFormat format = AvatarFormat.Auto, ushort size = 128) => CDN.GetUserAvatarUrl(Id, AvatarId, size, format);
+        public string GetAvatarUrl(ImageFormat format = ImageFormat.Auto, ushort size = 128) 
+            => CDN.GetUserAvatarUrl(Id, AvatarId, size, format);
         public DateTimeOffset CreatedAt => DateTimeUtils.FromSnowflake(Id);
         public string Discriminator => DiscriminatorValue.ToString("D4");
         public string Mention => MentionUtils.MentionUser(Id);
diff --git a/src/Discord.Net.WebSocket/Entities/Users/SocketUser.cs b/src/Discord.Net.WebSocket/Entities/Users/SocketUser.cs
index 5a0c22d36..5c73e3b6a 100644
--- a/src/Discord.Net.WebSocket/Entities/Users/SocketUser.cs
+++ b/src/Discord.Net.WebSocket/Entities/Users/SocketUser.cs
@@ -15,7 +15,8 @@ namespace Discord.WebSocket
         internal abstract SocketGlobalUser GlobalUser { get; }
         internal abstract SocketPresence Presence { get; set; }
 
-        public string GetAvatarUrl(AvatarFormat format = AvatarFormat.Auto, ushort size = 128) => CDN.GetUserAvatarUrl(Id, AvatarId, size, format);
+        public string GetAvatarUrl(ImageFormat format = ImageFormat.Auto, ushort size = 128) 
+            => CDN.GetUserAvatarUrl(Id, AvatarId, size, format);
         public DateTimeOffset CreatedAt => DateTimeUtils.FromSnowflake(Id);
         public string Discriminator => DiscriminatorValue.ToString("D4");
         public string Mention => MentionUtils.MentionUser(Id);