upd

src/exporter.py

@@ -131,8 +131,12 @@ def _export_pdf(images: list[Path], out: Path, meta: MangaMeta):
 def _export_pdf_pillow(images: list[Path], out: Path):
     from PIL import Image
     pil_images = [Image.open(p).convert("RGB") for p in images]
-    if pil_images:
-        pil_images[0].save(out, save_all=True, append_images=pil_images[1:], format="PDF")
+    try:
+        if pil_images:
+            pil_images[0].save(out, save_all=True, append_images=pil_images[1:], format="PDF")
+    finally:
+        for img in pil_images:
+            img.close()
 
 
 def _patch_pdf_meta(pdf_path: Path, meta: MangaMeta):