diff --git a/modules/services/serviceAi/subStructureFilling.py b/modules/services/serviceAi/subStructureFilling.py
index 1dba45a8..fae9a5bf 100644
--- a/modules/services/serviceAi/subStructureFilling.py
+++ b/modules/services/serviceAi/subStructureFilling.py
@@ -1722,6 +1722,7 @@ RETURN JSON:
       "contentPartIds": ["extracted_part_1"],
       "generationHint": "Include full text",
       "useAiCall": false,
+      "caption": "optional, only for image sections",
       "elements": []
     }}
   ]
@@ -1733,10 +1734,13 @@ EXAMPLES (all content types):
 - table: {{"id": "s3", "content_type": "table", "contentPartIds": ["extracted_1", "extracted_2"], "generationHint": "Create table", "useAiCall": true, "elements": []}}
 - heading: {{"id": "s4", "content_type": "heading", "contentPartIds": ["extracted_1"], "generationHint": "Extract heading", "useAiCall": true, "elements": []}}
 - code_block: {{"id": "s5", "content_type": "code_block", "contentPartIds": ["extracted_1"], "generationHint": "Format code", "useAiCall": true, "elements": []}}
-- image: {{"id": "s6", "content_type": "image", "contentPartIds": ["obj_1"], "generationHint": "Display image", "useAiCall": false, "elements": []}}
+- image: {{"id": "s6", "content_type": "image", "contentPartIds": ["obj_1"], "generationHint": "Display image", "caption": "Figure 1: Description of the image", "useAiCall": false, "elements": []}}
 - reference: {{"id": "s7", "content_type": "paragraph", "contentPartIds": ["ref_1"], "generationHint": "Reference", "useAiCall": false, "elements": []}}
 - NO CONTENT PARTS (generate from scratch): {{"id": "s8", "content_type": "paragraph", "contentPartIds": [], "generationHint": "Write a detailed professional paragraph explaining [specific topic or purpose]. Include [key points to cover]. Address [important aspects]. Conclude with [summary or recommendations].", "useAiCall": true, "elements": []}}
 
+IMAGE SECTIONS:
+- For image sections, always provide a "caption" field with a descriptive caption for the image.
+
 Return only valid JSON. Do not include any explanatory text outside the JSON.
 """
         return prompt