diff --git a/nodes/image/image_helpers.py b/nodes/image/image_helpers.py
index 669d267..eef8e11 100644
--- a/nodes/image/image_helpers.py
+++ b/nodes/image/image_helpers.py
@@ -1,3 +1,4 @@
+import fnmatch
 import os
 import random
 import string as S
@@ -7,58 +8,71 @@ import folder_paths as FP
 import numpy as NP
 from PIL import Image
 
+FORMAT_EXT = {
+    "PNG": ".png",
+    "JPEG": ".jpg",
+    "WEBP": ".webp",
+}
 
-def _save(
+class InvalidSavePathError(Exception):
+    pass
+
+def _build_filename(save_path, filename_mask):
+    count = sum(1 for f in os.scandir(save_path) if fnmatch.fnmatch(f.name, filename_mask)) + 1
+
+    return filename_mask.replace("*", f"{count:05}")
+
+
+def _build_save_path(output_path, subfolder, filename_prefix, filename_format, image_format):
+    save_path = os.path.join(output_path, subfolder)
+    if os.path.commonpath((output_path, os.path.abspath(save_path))) != output_path:
+        raise InvalidSavePathError("Saving image outside the output folder is not allowed.")
+
+    os.makedirs(save_path, exist_ok=True)
+
+    ext = FORMAT_EXT[image_format]
+
+    filename = ""
+    match filename_format:
+        case "name-###":
+            filename = _build_filename(save_path, f"{filename_prefix}-*{ext}")
+        case "date-name-###":
+            date = datetime.now().strftime("%Y-%m-%d")
+            filename = _build_filename(save_path, f"{date}-{filename_prefix}-*{ext}")
+        case "name-datetime":
+            timestamp = datetime.now().strftime("%Y%m%d-%H%M%S")
+            filename = f"{filename_prefix}-{timestamp}{ext}"
+        case _:
+            filename = f"{filename_prefix}{ext}"
+
+    return save_path, filename
+
+
+def _store_image(
         images,
-        prefix,
+        filename_prefix,
         output_path,
-        filename_format=None,
-        image_format="PNG",
-        quality=50,
-        compress_level=4
+        subfolder,
+        filename_format,
+        image_format,
+        quality,
+        compress_level
 ):
-    height, width = images[0].shape[:2]
-    save_path, filename, counter, subfolder, _ = FP.get_save_image_path(
-        prefix, output_path, height, width
-    )
-
     retval = list()
-    for (idx, image) in enumerate(images):
+    for image in images:
         img_np = 255. * image.cpu().numpy()
         timage = Image.fromarray(NP.clip(img_np, 0, 255).astype(NP.uint8))
-
-        match filename_format:
-            case "name-###":
-                filename = f"{filename}-{counter:05}"
-            case "date-name-###":
-                date = datetime.now().strftime("%Y-%m-%d")
-                filename = f"{date}-{filename}-{counter:05}"
-            case "name-datetime":
-                timestamp = datetime.now().strftime("%Y%m%d-%H%M%S")
-                filename = f"{filename}-{timestamp}"
-            case _:
-                pass
-
-        params = {}
-        match image_format:
-            case "PNG":
-                filename += ".png"
-                params["compress_level"] = compress_level
-            case "JPEG":
-                filename += ".jpg"
-                params["quality"] = quality
-            case "WEBP":
-                filename += ".webp"
-                params["quality"] = quality
-
+        save_path, filename = _build_save_path(
+            output_path, subfolder, filename_prefix, filename_format, image_format
+        )
+        params = {"compress_level": compress_level} if image_format == "PNG" else {"quality": quality}
         timage.save(os.path.join(save_path, filename), format=image_format, **params)
 
         retval.append({
             "filename": filename,
             "subfolder": subfolder,
-            "type": "temp" if prefix.startswith("tmp") else "output"
+            "type": "temp" if filename_prefix.startswith("tmp") else "output"
         })
-        counter += 1
 
     return retval
 
@@ -73,12 +87,12 @@ def store(
         compress_level
 ):
     output_folder = FP.get_output_directory()
-    prefix = os.path.join(subfolder, filename_prefix)
 
-    return _save(
+    return _store_image(
         images=image,
-        prefix=prefix,
+        filename_prefix=filename_prefix,
         output_path=output_folder,
+        subfolder=subfolder,
         filename_format=filename_format,
         image_format=image_format,
         quality=image_quality,
@@ -91,8 +105,8 @@ def preview(image, filename_prefix):
     rand = "".join(random.choices(S.ascii_lowercase, k=5))
     prefix = f"tmp-{filename_prefix}-{rand}"
 
-    return _save(
+    return _store_image(
         images=image,
-        prefix=prefix,
+        filename_prefix=prefix,
         output_path=temp_dir,
     )