Allowed the Batch Processing assistant to process images (#1087)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/MindWork AI Studio/Provider/LLMProvidersExtensions.cs

@@ -288,6 +288,27 @@ public static class LLMProvidersExtensions
         _ => false,
     };
 
+    /// <summary>
+    /// The largest image file, in bytes, which the provider accepts in a request, where it states one.
+    /// </summary>
+    /// <remarks>
+    /// The limit belongs to the API of the provider, not to the model: the same model may accept
+    /// larger images through another provider. What we actually send is asked through
+    /// IImageSourceExtensions.MaxImageSizeBytesFor, which also applies our own limit.
+    /// </remarks>
+    /// <param name="llmProvider">The provider to check.</param>
+    /// <returns>The size limit of one image file, or null when the provider states none we know of.</returns>
+    public static long? GetMaxImageSizeBytes(this LLMProviders llmProvider) => llmProvider switch
+    {
+        //
+        // Anthropic accepts at most 5 MiB (5,242,880 bytes) of base64 per image. Base64 needs four
+        // characters for every three bytes, which leaves 3,932,160 bytes for the image file itself:
+        //
+        LLMProviders.ANTHROPIC => 3_932_160,
+
+        _ => null,
+    };
+
     /// <summary>
     /// Creates a new provider instance based on the provider value.
     /// </summary>