diff --git a/.github/test/Dockerfile-alpine b/.github/test/Dockerfile-alpine
index 0e63982d9..029cb1dc0 100644
--- a/.github/test/Dockerfile-alpine
+++ b/.github/test/Dockerfile-alpine
@@ -7,6 +7,8 @@ ENV PYTHONUNBUFFERED=1
 
 COPY requirements.txt /requirements.txt
 
+ARG TARGETPLATFORM
+
 RUN \
  apk add --update --no-cache --virtual=build-dependencies \
     build-base \
@@ -31,12 +33,18 @@ RUN \
     glib \
     libsm \
     libxext \
-    libxrender \
-    py3-opencv && \
+    libxrender && \
+  case "$TARGETPLATFORM" in \
+    linux/arm/v7|linux/arm/v8) \
+      echo "INFO: Skipping py3-opencv on $TARGETPLATFORM (using pixelmatch fallback)" \
+      ;; \
+    *) \
+      apk add --update --no-cache py3-opencv || echo "WARN: py3-opencv install failed, using pixelmatch fallback" \
+      ;; \
+  esac && \
   echo "**** pip3 install test of changedetection.io ****" && \
   python3 -m venv /lsiopy  && \
   pip install -U pip wheel setuptools && \
-  grep -v "opencv-python-headless" /requirements.txt > /requirements-alpine.txt && \
-  pip install -U --no-cache-dir --find-links https://wheel-index.linuxserver.io/alpine-3.22/ -r /requirements-alpine.txt && \
+  pip install -U --no-cache-dir --find-links https://wheel-index.linuxserver.io/alpine-3.22/ -r /requirements.txt && \
   apk del --purge \
     build-dependencies
diff --git a/Dockerfile b/Dockerfile
index 5373fdae1..c0d6a18d4 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -55,6 +55,25 @@ RUN --mount=type=cache,id=pip,sharing=locked,target=/tmp/pip-cache \
   playwright~=1.56.0 \
   || echo "WARN: Failed to install Playwright. The application can still run, but the Playwright option will be disabled."
 
+# OpenCV is optional for fast image comparison (pixelmatch is the fallback)
+# Skip on arm/v7 and arm/v8 where builds take weeks - excluded from requirements.txt
+ARG TARGETPLATFORM
+RUN --mount=type=cache,id=pip,sharing=locked,target=/tmp/pip-cache \
+  case "$TARGETPLATFORM" in \
+    linux/arm/v7|linux/arm/v8) \
+      echo "INFO: Skipping OpenCV on $TARGETPLATFORM (build takes too long), using pixelmatch fallback" \
+      ;; \
+    *) \
+      pip install \
+        --prefer-binary \
+        --extra-index-url https://www.piwheels.org/simple \
+        --cache-dir=/tmp/pip-cache \
+        --target=/dependencies \
+        opencv-python-headless>=4.8.0.76 \
+        || echo "WARN: OpenCV install failed, will use pixelmatch fallback" \
+      ;; \
+  esac
+
 
 # Final image stage
 FROM python:${PYTHON_VERSION}-slim-bookworm
diff --git a/requirements.txt b/requirements.txt
index c73b20e56..aac51fe65 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -73,9 +73,10 @@ lxml >=4.8.0,!=5.2.0,!=5.2.1,<7
 elementpath==5.0.4
 
 # For fast image comparison in screenshot change detection
-# opencv-python-headless provides cv2 without GUI dependencies (smaller, faster)
-# Note: OpenCV uses 4-part versioning (e.g., 4.8.0.76)
-opencv-python-headless>=4.8.0.76
+# opencv-python-headless is OPTIONAL (excluded from requirements.txt)
+# - Installed conditionally via Dockerfile (skipped on arm/v7 and arm/v8 due to long build times)
+# - Pixelmatch is used as fallback when OpenCV is unavailable
+# - To install manually: pip install opencv-python-headless>=4.8.0.76
 
 selenium~=4.31.0