diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index a2bf7fda0..b5c6c21b9 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -2,6 +2,7 @@
 
 ==== Unreleased
  * FIX: Cookie使用時に「Listの発言取得に公式RTを含める」の設定が適用されない不具合を修正
+ * FIX: Twitterアカウントでの画像を添付したツイートの投稿がエラーになる不具合を修正
 
 ==== Ver 3.15.0(2024/06/14)
  * NEW: Misskeyでのノート投稿時のファイル添付に対応しました
diff --git a/OpenTween/Api/GraphQL/CreateTweetRequest.cs b/OpenTween/Api/GraphQL/CreateTweetRequest.cs
index b268cb83a..d91da2527 100644
--- a/OpenTween/Api/GraphQL/CreateTweetRequest.cs
+++ b/OpenTween/Api/GraphQL/CreateTweetRequest.cs
@@ -30,6 +30,7 @@
 using OpenTween.Api.DataModel;
 using OpenTween.Connection;
 using OpenTween.Models;
+using OpenTween.SocialProtocol.Twitter;
 
 namespace OpenTween.Api.GraphQL
 {
@@ -43,7 +44,7 @@ public class CreateTweetRequest
 
         public TwitterUserId[] ExcludeReplyUserIds { get; set; } = Array.Empty<TwitterUserId>();
 
-        public string[] MediaIds { get; set; } = Array.Empty<string>();
+        public TwitterMediaId[] MediaIds { get; set; } = Array.Empty<TwitterMediaId>();
 
         public string? AttachmentUrl { get; set; }
 
@@ -112,7 +113,7 @@ public string CreateRequestBody()
                         ? new(
                             MediaEntities: this.MediaIds
                                 .Select(x => new VariableMediaEntity(
-                                    MediaId: x,
+                                    MediaId: x.Id,
                                     TaggedUsers: Array.Empty<string>()
                                 ))
                                 .ToArray(),
diff --git a/OpenTween/Twitter.cs b/OpenTween/Twitter.cs
index b014d068b..0d1458bb2 100644
--- a/OpenTween/Twitter.cs
+++ b/OpenTween/Twitter.cs
@@ -228,7 +228,7 @@ await this.SendDirectMessage(param.Text, mediaId)
                     TweetText = param.Text,
                     InReplyToTweetId = param.InReplyTo?.StatusId.ToTwitterStatusId(),
                     ExcludeReplyUserIds = param.ExcludeReplyUserIds.OfType<TwitterUserId>().ToArray(),
-                    MediaIds = param.MediaIds.Select(x => x.ToString()).ToArray(),
+                    MediaIds = param.MediaIds.ToArray(),
                     AttachmentUrl = param.AttachmentUrl,
                 };