From e739468a854e6817cb79889677075b9d8c80a081 Mon Sep 17 00:00:00 2001
From: Thorsten Sommer <SommerEngineering@users.noreply.github.com>
Date: Mon, 10 Aug 2026 19:58:39 +0200
Subject: [PATCH] Fixed slide images reaching the AI as raw Base64 data

---
 .../Tools/ContentStreamSseHandler.cs          | 27 ++++++++++++++++++-
 .../Tools/DocumentManager.cs                  |  7 +++--
 .../Tools/SlideImageContent.cs                | 10 ++++---
 app/MindWork AI Studio/Tools/SlideManager.cs  | 16 +++++------
 4 files changed, 43 insertions(+), 17 deletions(-)

diff --git a/app/MindWork AI Studio/Tools/ContentStreamSseHandler.cs b/app/MindWork AI Studio/Tools/ContentStreamSseHandler.cs
index d333b7b1..564186be 100644
--- a/app/MindWork AI Studio/Tools/ContentStreamSseHandler.cs	
+++ b/app/MindWork AI Studio/Tools/ContentStreamSseHandler.cs	
@@ -132,7 +132,32 @@ public static class ContentStreamSseHandler
         CHUNKED_IMAGES.Remove(id, out _);
         return base64Image;
     }
-    
+
+    /// <summary>
+    /// Assembles the collected segments of an image into a Markdown image.
+    /// </summary>
+    /// <remarks>
+    /// Handing the naked Base64 data to the AI says nothing: it is neither readable text nor an
+    /// image it could look at. Only the data URI makes it one, so every reader must embed its
+    /// images this way.
+    /// </remarks>
+    /// <param name="id">The ID of the image to assemble.</param>
+    /// <param name="mediaType">The media type the runtime reported, if any.</param>
+    /// <returns>The Markdown image, or null when no data was collected for that ID.</returns>
+    public static string? BuildImageMarkdown(string id, string? mediaType)
+    {
+        var base64Image = BuildImage(id);
+        if (string.IsNullOrWhiteSpace(base64Image))
+            return null;
+
+        //
+        // Both readers compress their images, and that compression produces JPEG. A runtime which
+        // does not report the media type therefore delivered JPEG as well.
+        //
+        var imageMediaType = string.IsNullOrWhiteSpace(mediaType) ? "image/jpeg" : mediaType;
+        return $"![Image](data:{imageMediaType};base64,{base64Image})";
+    }
+
     public static string? Clear(string streamId)
     {
         if (string.IsNullOrWhiteSpace(streamId))
diff --git a/app/MindWork AI Studio/Tools/DocumentManager.cs b/app/MindWork AI Studio/Tools/DocumentManager.cs
index 875a4771..8183987e 100644
--- a/app/MindWork AI Studio/Tools/DocumentManager.cs	
+++ b/app/MindWork AI Studio/Tools/DocumentManager.cs	
@@ -31,12 +31,11 @@ public sealed class DocumentManager
 
         if (ContentStreamSseHandler.ProcessImageSegment(image.Id, image))
         {
-            var base64 = ContentStreamSseHandler.BuildImage(image.Id);
-            if (!string.IsNullOrWhiteSpace(base64))
+            var markdownImage = ContentStreamSseHandler.BuildImageMarkdown(image.Id, image.MediaType);
+            if (markdownImage is not null)
             {
-                var mediaType = string.IsNullOrWhiteSpace(image.MediaType) ? "image/jpeg" : image.MediaType;
                 this.currentPageContent.AppendLine();
-                this.currentPageContent.AppendLine($"![Image](data:{mediaType};base64,{base64})");
+                this.currentPageContent.AppendLine(markdownImage);
             }
         }
 
diff --git a/app/MindWork AI Studio/Tools/SlideImageContent.cs b/app/MindWork AI Studio/Tools/SlideImageContent.cs
index ec261436..10dc6add 100644
--- a/app/MindWork AI Studio/Tools/SlideImageContent.cs	
+++ b/app/MindWork AI Studio/Tools/SlideImageContent.cs	
@@ -1,8 +1,10 @@
-using System.Text;
-
 namespace AIStudio.Tools;
 
-public sealed class SlideImageContent(string base64Image) : ISlideContent
+/// <summary>
+/// An image of a slide, ready to be appended to the slide's Markdown.
+/// </summary>
+/// <param name="markdownImage">The image as a Markdown image with an embedded data URI.</param>
+public sealed class SlideImageContent(string markdownImage) : ISlideContent
 {
-    public StringBuilder Base64Image => new(base64Image);
+    public string MarkdownImage => markdownImage;
 }
\ No newline at end of file
diff --git a/app/MindWork AI Studio/Tools/SlideManager.cs b/app/MindWork AI Studio/Tools/SlideManager.cs
index 47407bd1..f6ed1ea6 100644
--- a/app/MindWork AI Studio/Tools/SlideManager.cs	
+++ b/app/MindWork AI Studio/Tools/SlideManager.cs	
@@ -52,11 +52,11 @@ public sealed class SlideManager
             //
             if (addImage)
             {
-                var img = ContentStreamSseHandler.BuildImage(image!.Id!);
-                var slideImage = new SlideImageContent(img);
-                createdSlide.Content.Add(slideImage);
+                var markdownImage = ContentStreamSseHandler.BuildImageMarkdown(image!.Id!, image.MediaType);
+                if (markdownImage is not null)
+                    createdSlide.Content.Add(new SlideImageContent(markdownImage));
             }
-            
+
             this.slides[slideNumber] = createdSlide;
         }
         else
@@ -75,9 +75,9 @@ public sealed class SlideManager
             // Add any image content?
             if (addImage)
             {
-                var img = ContentStreamSseHandler.BuildImage(image!.Id!);
-                var slideImage = new SlideImageContent(img);
-                slide.Content.Add(slideImage);
+                var markdownImage = ContentStreamSseHandler.BuildImageMarkdown(image!.Id!, image.MediaType);
+                if (markdownImage is not null)
+                    slide.Content.Add(new SlideImageContent(markdownImage));
             }
         }
     }
@@ -96,7 +96,7 @@ public sealed class SlideManager
 
             foreach (var image in slide.Content.OfType<SlideImageContent>())
             {
-                content.AppendLine(image.Base64Image.ToString());
+                content.AppendLine(image.MarkdownImage);
                 content.AppendLine();
             }
         }