diff --git a/mkrelease.sh b/mkrelease.sh
new file mode 100755
index 0000000..7ad9f31
--- /dev/null
+++ b/mkrelease.sh
@@ -0,0 +1,16 @@
+#!/bin/bash -ex
+
+JSON="$(realpath -e $1)"
+BASEDIR="${JSON%/*}"
+
+IMAGE="${BASEDIR}/$(jq -r '.name' ${JSON})-$(jq -r '.version' ${JSON})"
+
+(
+    cd "$IMAGE"
+    [[ -f sha512sum.txt ]] || sha512sum * > sha512sum.txt
+    [[ -f sha512sum.txt.sig ]] || gpg2 --detach-sign sha512sum.txt
+)
+
+if ! [[ -e "$IMAGE".tgz ]]; then
+    tar cf - -C "${IMAGE%/*}" "${IMAGE##*/}" | pigz -c > "$IMAGE".tgz
+fi