Enhance WernstromService to detect actual MIME type from image bytes, improving accuracy over Discord's reported type

Author: rschili

…thub/instructions/saneai.instructions.md …hub/instructions/copilot-instructions.md.github/instructions/saneai.instructions.md renamed to .github/instructions/copilot-instructions.md .github/instructions/saneai.instructions.md renamed to .github/instructions/copilot-instructions.md

@@ -1,7 +1,3 @@
----
-applyTo: 'src/RSBotWorks/SaneAI/**,src/RSBotWorks.Tests/SaneAI/**,src/RSBotWorks.Tests/Explicit/SaneAI/**,src/SaneAI.Demo/**'
----
-
 # SaneAI — Raw JSON AI Abstraction
 
 SaneAI is a custom AI API abstraction layer that bypasses third-party SDKs entirely. It talks directly to provider REST APIs using raw JSON, so new model features/settings can be added immediately without waiting for SDK updates.

src/Wernstrom/WernstromService.Images.cs

@@ -50,6 +50,17 @@ public partial class WernstromService
                 mimeType = "image/jpeg"; // Assume JPEG after processing
                 isResized = true;
             }
+            else
+            {
+                // Detect actual MIME type from image bytes — Discord's ContentType can be wrong
+                var detectedFormat = SixLabors.ImageSharp.Image.DetectFormat(imageData);
+                if (detectedFormat != null && detectedFormat.DefaultMimeType != mimeType)
+                {
+                    Logger.LogWarning("Discord reported MIME type {DiscordMimeType} but image bytes indicate {DetectedMimeType} for {Filename}. Using detected type.",
+                        mimeType, detectedFormat.DefaultMimeType, attachment.Filename);
+                    mimeType = detectedFormat.DefaultMimeType;
+                }
+            }
             if (imageData == null || imageData.Length == 0)
             {
                 Logger.LogWarning($"Failed to download or process image: {attachment.Filename}");