Restore PNG metadata writing in sd_image_pipeline after refactor

core/pipelines/sd_image_pipeline.py

@@ -239,9 +239,38 @@ class SdImagePipeline(BasePipeline):
                 assembler=assembler, 
                 progress=progress
             )
-            
-            # The workflow already saved images and returned a deduplicated list of file paths.
+            # -----------------------------------------------------------------
+            # Add generation metadata to the saved PNG files (if they exist).
+            # The original pipeline saved each image with a "parameters" field
+            # containing the prompt, seed, steps, sampler, etc.  Some recent
+            # refactoring removed that block, causing the Gallery to have no
+            # metadata to display.  We restore the behaviour here.
+            # -----------------------------------------------------------------
+            from PIL import Image, PngImagePlugin
+            import json, random, os
+            # Build the same param string used previously in `_gpu_logic`
+            params_string = f"{ui_inputs['positive_prompt']}\nNegative prompt: {ui_inputs['negative_prompt']}\n"
+            params_string += f"Steps: {ui_inputs['num_inference_steps']}, Sampler: {ui_inputs['sampler']}, Scheduler: {ui_inputs['scheduler']}, CFG scale: {ui_inputs['guidance_scale']}, Seed: {ui_inputs['seed']}, Size: {ui_inputs.get('width', 'N/A')}x{ui_inputs.get('height', 'N/A')}, Base Model: {model_display_name}"
+            if ui_inputs['task_type'] != 'txt2img':
+                params_string += f", Denoise: {ui_inputs.get('denoise', '')}"
+            if ui_inputs.get('clip_skip') and ui_inputs['clip_skip'] != 1:
+                params_string += f", Clip skip: {abs(ui_inputs['clip_skip'])}"
+            if loras_string:
+                params_string += f", {loras_string}"
+            # Attach metadata to each generated PNG (if it exists)
+            for path in results:
+                if not os.path.isfile(path):
+                    continue
+                try:
+                    with Image.open(path) as im:
+                        meta = PngImagePlugin.PngInfo()
+                        meta.add_text("parameters", params_string)
+                        # Preserve existing info if any (e.g., EXIF)
+                        im.save(path, "PNG", pnginfo=meta)
+                except Exception as e:
+                    print(f"[WARN] Could not write generation metadata to {path}: {e}")
             return results
+            
         finally:
             for temp_file in temp_files_to_clean:
                 if temp_file and os.path.exists(temp_file):