Initial commit of new flow

docker/pictures/Dockerfile

@@ -0,0 +1,14 @@
+FROM alpine:3.15.4
+RUN apk add --no-cache imagemagick=7.1.0.16-r0
+
+COPY "build.sh" "/build.sh"
+
+RUN chmod +x /build.sh && \
+	mkdir /sentinels && \
+	chmod a+rwx /sentinels && \
+	addgroup -S pictures && adduser -S pictures -G pictures
+
+USER pictures
+WORKDIR /home/pictures
+
+ENTRYPOINT []

docker/pictures/build.sh

@@ -0,0 +1,13 @@
+#!/bin/sh
+
+TO_SCAN="$1"
+
+SHELL="/bin/sh"
+
+# For some reason, using $0 instead of `sh` makes Shellcheck warn about the single-quotes not expanding expressions
+# shellcheck disable=SC2016
+find "$TO_SCAN" -type f ! -name '*-thumb.jpg' -name '*.jpg' -exec "$SHELL" -c '
+  if [ -f "${@%.*}-thumb.jpg" ]; then exit 0; fi;
+  echo "$@"
+  convert "$@" -thumbnail 100x100^ -gravity center -extent 100x100 "${1%.*}-thumb.jpg"
+' -- {} \; || exit 1