Pin opencv-python 4.5.2.52 (cp36 wheel) + libgl1

Dockerfile

@@ -2,8 +2,8 @@
 # Built for a Hugging Face Docker Space (listens on 7860).
 FROM python:3.6-slim
 
-# system lib OpenCV needs (base image is Debian bullseye — repos are live, no archive workaround)
-RUN apt-get update && apt-get install -y --no-install-recommends libglib2.0-0 && rm -rf /var/lib/apt/lists/*
+# system libs OpenCV needs at runtime (bullseye repos are live)
+RUN apt-get update && apt-get install -y --no-install-recommends libglib2.0-0 libgl1-mesa-glx && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app
 
@@ -17,7 +17,7 @@ RUN pip install --no-cache-dir \
     keras==2.0.8 \
     scipy==1.5.4 \
     scikit-image==0.17.2 \
-    "opencv-python-headless==4.5.2.52" \
+    "opencv-python==4.5.2.52" \
     Pillow==8.2.0 \
     imgaug==0.4.0 \
     Cython==0.29.23 \