diff --git a/weave b/weave
index 88fc10bd..8179f930 100755
--- a/weave
+++ b/weave
@@ -33,8 +33,18 @@ usage() {
 
 [ $# -gt 0 ] || usage
 
-IMAGE=zettio/weave
-DNS_IMAGE=zettio/weavedns
+if [ "$SCRIPT_VERSION" = "(unreleased version)" ] ; then
+    IMAGE_VERSION=latest
+else
+    IMAGE_VERSION=$SCRIPT_VERSION
+fi
+
+IMAGE_VERSION=${VERSION:-$IMAGE_VERSION}
+
+BASE_IMAGE=zettio/weave
+BASE_DNS_IMAGE=zettio/weavedns
+IMAGE=$BASE_IMAGE:$IMAGE_VERSION
+DNS_IMAGE=$BASE_DNS_IMAGE:$IMAGE_VERSION
 CONTAINER_NAME=weave
 DNS_CONTAINER_NAME=weavedns
 BRIDGE=weave
@@ -358,9 +368,16 @@ check_not_running() {
             echo "$1 is already running." >&2
             exit 1
             ;;
+        "true $2:"*)
+            echo "$1 is already running." >&2
+            exit 1
+            ;;
         "false $2")
             docker rm $1 >/dev/null
             ;;
+        "false $2:"*)
+            docker rm $1 >/dev/null
+            ;;
         true*)
             echo "Found another running container named '$1'. Aborting." >&2
             exit 1
@@ -429,7 +446,7 @@ DOCKER_VERSION_PATCH=$(echo "$DOCKER_VERSION" | cut -d. -f 3)
 
 case "$COMMAND" in
     launch)
-        check_not_running $CONTAINER_NAME $IMAGE
+        check_not_running $CONTAINER_NAME $BASE_IMAGE
         create_bridge
         # We set the router name to the bridge mac since that is
         # stable across re-creations of the containers.
@@ -466,7 +483,7 @@ case "$COMMAND" in
         [ $# -gt 0 ] || usage
         CIDR=$1
         shift 1
-        check_not_running $DNS_CONTAINER_NAME $DNS_IMAGE
+        check_not_running $DNS_CONTAINER_NAME $BASE_DNS_IMAGE
         create_bridge
         docker_bridge_ip
         DNS_CONTAINER=$(docker run --privileged -d --name=$DNS_CONTAINER_NAME \