diff --git a/bin/caesiumclt.exe b/bin/caesiumclt.exe
index 88c16ae..9731e9a 100644
Binary files a/bin/caesiumclt.exe and b/bin/caesiumclt.exe differ
diff --git a/install_and_run.bat b/install_and_run.bat
index 9a8ec51..17cb269 100644
--- a/install_and_run.bat
+++ b/install_and_run.bat
@@ -12,7 +12,7 @@ set "SELF_DIR=%~dp0"
 set "SCRIPT=%SELF_DIR%pptx_image_compress.py"
 
 rem ---- Python Embeddable config ----
-set "PY_EMBED_VERSION=3.13.9"
+set "PY_EMBED_VERSION=3.14.4"
 set "PY_EMBED_ZIP=python-%PY_EMBED_VERSION%-embed-amd64.zip"
 set "PY_EMBED_URL=https://www.python.org/ftp/python/%PY_EMBED_VERSION%/%PY_EMBED_ZIP%"
 set "PY_DIR=%SELF_DIR%python-embed"
diff --git a/pptx_image_compress.py b/pptx_image_compress.py
index b1061d1..044e67a 100644
--- a/pptx_image_compress.py
+++ b/pptx_image_compress.py
@@ -18,6 +18,8 @@ Highlights:
 
 import argparse
 import os
+import re
+import xml.etree.ElementTree as ET
 import sys
 import zipfile
 import tempfile
@@ -30,6 +32,8 @@ from pathlib import Path
 from datetime import timedelta
 from concurrent.futures import ThreadPoolExecutor, as_completed
 from threading import Lock
+from typing import List, Optional
+
 
 __version__ = "1.1.4"
 
@@ -117,6 +121,38 @@ def format_duration(seconds: float) -> str:
         return f"{hms}.{frac[:2]}"
     return base
 
+def get_slide_numbers_for_image(rels_dir: str, image_filename: str) -> Optional[List[int]]:
+    """
+    Durchsucht alle .rels-Dateien im angegebenen Verzeichnis und gibt die Slide-Nummern zurück,
+    in denen die angegebene Bilddatei referenziert wird.
+
+    :param rels_dir: Pfad zum Verzeichnis ppt/slides/_rels
+    :param image_filename: z. B. 'image80.png'
+    :return: Liste von Slide-Nummern oder None
+    """
+    slide_numbers = []
+
+    for rels_file in os.listdir(rels_dir):
+        if rels_file.startswith("slide") and rels_file.endswith(".xml.rels"):
+            rels_path = os.path.join(rels_dir, rels_file)
+            try:
+                tree = ET.parse(rels_path)
+                root = tree.getroot()
+                for rel in root.findall(".//{http://schemas.openxmlformats.org/package/2006/relationships}Relationship"):
+                    target = rel.attrib.get("Target", "")
+                    if image_filename in target:
+                        match = re.search(r"slide(\d+).xml.rels", rels_file)
+                        if match:
+                            slide_number = int(match.group(1))
+                            slide_numbers.append(slide_number)
+            except ET.ParseError:
+                print(f"Fehler beim Parsen von {rels_file}")
+
+    return slide_numbers if slide_numbers else None
+
+
+
+
 # -------------------- Core per-deck processing --------------------
 def process_single_deck(input_pptx: Path, output_pptx: Path, threads: int, quality: int) -> dict:
     start_time = time.perf_counter()
@@ -143,7 +179,7 @@ def process_single_deck(input_pptx: Path, output_pptx: Path, threads: int, quali
 
         log_file = output_pptx.with_suffix(".log.csv")
         ensure_clean_file(log_file)
-        log_lines = ["image_name;size_before(kb);size_after(kb);saving(kb);saving_percent(%)\n"]
+        log_lines = ["image_name;size_before(kb);size_after(kb);saving(kb);saving_percent(%);in_slide_number\n"]
 
         size_before = input_pptx.stat().st_size
         result["size_before"] = size_before
@@ -151,8 +187,11 @@ def process_single_deck(input_pptx: Path, output_pptx: Path, threads: int, quali
         with zipfile.ZipFile(input_pptx, "r") as z:
             z.extractall(work_dir)
 
+        slides_dir  = work_dir / "ppt" / "slides"
         media_dir = work_dir / "ppt" / "media"
+        
         images = []
+
         if media_dir.exists():
             for f in sorted(media_dir.iterdir()):
                 if f.is_file() and f.suffix.lower() in ALLOWED_EXT:
@@ -174,7 +213,15 @@ def process_single_deck(input_pptx: Path, output_pptx: Path, threads: int, quali
             ext = img_path.suffix.lower()
             orig_size = img_path.stat().st_size
             chosen_size = orig_size
+            found_in_slide=None
+            slide_nr=""
+
             try:
+                found_in_slide = get_slide_numbers_for_image(slides_dir.name, img_path.name) 
+                if found_in_slide is None:
+                    slide_nr = "NOT_USED"
+                else:
+                    slide_nr = str(found_in_slide)
                 out_sub = scratch_dir / f"img_{idx:06d}"
                 caesium_out = compress_with_caesium(img_path, out_sub, caesium_threads, quality)
                 if caesium_out and caesium_out.exists():
@@ -189,8 +236,9 @@ def process_single_deck(input_pptx: Path, output_pptx: Path, threads: int, quali
             finally:
                 saving = orig_size - chosen_size
                 saving_percent = round((saving / orig_size) * 100, 2) if orig_size > 0 else 0.0
+
                 with lock:
-                    log_lines.append(f"{img_path.name};{human_kb(orig_size)};{human_kb(chosen_size)};{human_kb(saving)};{saving_percent}\n")
+                    log_lines.append(f"{img_path.name};{human_kb(orig_size)};{human_kb(chosen_size)};{human_kb(saving)};{saving_percent};{slide_nr}\n")
                     done_count += 1
                     print_progress(done_count, total)
 
diff --git a/samples/README.txt b/samples/README.txt
deleted file mode 100644
index 517e728..0000000
--- a/samples/README.txt
+++ /dev/null
@@ -1 +0,0 @@
-Place your PPTX files here for testing, or use -i with a full path.