Handle image input as string paths for MMLMs (#1958)

* Update mm_chat.py

Handle string image (paths)

* chore: lint

---------

Co-authored-by: Wing Lian <wing.lian@gmail.com>

src/axolotl/utils/collators/mm_chat.py

@@ -4,6 +4,7 @@ Collators for multi-modal chat messages and packing
 from dataclasses import dataclass
 from typing import Any, Dict, List, Optional, Union
 
+from PIL import Image
 from transformers import PreTrainedTokenizerBase, ProcessorMixin
 from transformers.data.data_collator import DataCollatorMixin
 from transformers.utils import PaddingStrategy
@@ -52,7 +53,12 @@ class MultiModalChatDataCollator(DataCollatorMixin):
             )
             for example in examples
         ]
-        images = [example["images"] for example in examples]
+        images = [
+            Image.open(example["images"])
+            if isinstance(example["images"], str)
+            else example["images"]
+            for example in examples
+        ]
 
         if max_images > 0:
             images = [img_batch[:max_images] for img_batch in images]