diff --git a/src/bridge/images.py b/src/bridge/images.py
index 3deb343..0b36bf2 100644
--- a/src/bridge/images.py
+++ b/src/bridge/images.py
@@ -1,10 +1,27 @@
+import glob
 import os
+import time
 import uuid
 import numpy as np
 import torch
 from PIL import Image
 
 
+def _reap_old(out_dir: str, keep: str) -> None:
+    """Delete img_*.png in out_dir older than COMFY_BRIDGE_TMP_TTL (default
+    3600s) so the temp dir doesn't grow forever. Never touches `keep`."""
+    ttl = float(os.environ.get("COMFY_BRIDGE_TMP_TTL", "3600"))
+    cutoff = time.time() - ttl
+    for f in glob.glob(os.path.join(out_dir, "img_*.png")):
+        if f == keep:
+            continue
+        try:
+            if os.path.getmtime(f) < cutoff:
+                os.unlink(f)
+        except (FileNotFoundError, OSError):
+            pass  # races / permission churn -> best-effort
+
+
 def save_tensor_png(tensor: torch.Tensor, out_dir: str) -> str:
     """ComfyUI IMAGE [B,H,W,C] float 0..1 -> PNG file, returns path."""
     os.makedirs(out_dir, exist_ok=True)
@@ -14,6 +31,7 @@ def save_tensor_png(tensor: torch.Tensor, out_dir: str) -> str:
     img = Image.fromarray(arr, mode="RGB")
     path = os.path.join(out_dir, f"img_{uuid.uuid4().hex}.png")
     img.save(path)
+    _reap_old(out_dir, keep=path)
     return path
 
 
diff --git a/tests/bridge/test_images_gc.py b/tests/bridge/test_images_gc.py
new file mode 100644
index 0000000..feb14a5
--- /dev/null
+++ b/tests/bridge/test_images_gc.py
@@ -0,0 +1,39 @@
+"""Age-based GC of temp PNGs: save_tensor_png reaps img_*.png older than the
+TTL (env COMFY_BRIDGE_TMP_TTL, default 3600s) while keeping recent files and
+the file it just wrote."""
+import os
+import time
+
+import torch
+
+from src.bridge import images
+
+
+def _tensor():
+    return torch.zeros(1, 4, 4, 3)
+
+
+def test_old_temp_image_is_reaped(tmp_path, monkeypatch):
+    monkeypatch.setenv("COMFY_BRIDGE_TMP_TTL", "3600")
+    old = tmp_path / "img_old.png"
+    old.write_bytes(b"stale")
+    backdated = time.time() - 7200  # 2h old, past the 1h TTL
+    os.utime(old, (backdated, backdated))
+
+    new_path = images.save_tensor_png(_tensor(), str(tmp_path))
+
+    assert not old.exists(), "stale temp image should have been reaped"
+    assert os.path.exists(new_path), "freshly written image must survive"
+
+
+def test_recent_temp_image_is_kept(tmp_path, monkeypatch):
+    monkeypatch.setenv("COMFY_BRIDGE_TMP_TTL", "3600")
+    recent = tmp_path / "img_recent.png"
+    recent.write_bytes(b"fresh")
+    recent_mtime = time.time() - 60  # 1 min old, within TTL
+    os.utime(recent, (recent_mtime, recent_mtime))
+
+    new_path = images.save_tensor_png(_tensor(), str(tmp_path))
+
+    assert recent.exists(), "recent temp image within TTL must be kept"
+    assert os.path.exists(new_path)