diff --git a/Dockerfile b/Dockerfile
index ab81472..4350e0f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -11,19 +11,19 @@ RUN dnf -y upgrade-minimal && \
 # it all every time we change the requirements :-/
 
 # install Java
-RUN url="https://download.java.net/java/GA/jdk15.0.1/51f4f36ad4ef43e39d0dfdbaf6549e32/9/GPL/openjdk-15.0.1_linux-x64_bin.tar.gz" ; \
-    curl -s "$url" | tar -C /usr/bin/ -xz
+ARG JAVA_URL=https://download.java.net/java/GA/jdk15.0.1/51f4f36ad4ef43e39d0dfdbaf6549e32/9/GPL/openjdk-15.0.1_linux-x64_bin.tar.gz
+RUN curl -s "$JAVA_URL" | tar -xz -C /usr/bin/
 
 # install Firefox
-RUN dnf install -y wget bzip2 xorg-x11-server-Xvfb gtk3 dbus-glib && \
-    wget -qO- "https://ftp.mozilla.org/pub/firefox/releases/94.0.2/linux-x86_64/en-US/firefox-94.0.2.tar.bz2" \
-        | tar -C /usr/local/ -jx && \
+ARG FIREFOX_URL=https://ftp.mozilla.org/pub/firefox/releases/94.0.2/linux-x86_64/en-US/firefox-94.0.2.tar.bz2
+RUN dnf install -y bzip2 xorg-x11-server-Xvfb gtk3 dbus-glib && \
+    curl -s "$FIREFOX_URL" | tar -jx -C /usr/local/ && \
     ln -s /usr/local/firefox/firefox /usr/bin/firefox && \
     echo "exclude=firefox" >>/etc/dnf/dnf.conf
 
 # install geckodriver
-RUN curl -sL "https://github.com/mozilla/geckodriver/releases/download/v0.30.0/geckodriver-v0.30.0-linux64.tar.gz" \
-    | tar -C /usr/bin/ -xz
+ARG GECKODRIVER_URL=https://github.com/mozilla/geckodriver/releases/download/v0.30.0/geckodriver-v0.30.0-linux64.tar.gz
+RUN curl -sL "$GECKODRIVER_URL" | tar -xz -C /usr/bin/
 
 # clean up
 RUN dnf clean all
diff --git a/run-container.sh b/run-container.sh
index 948be08..a3c7066 100755
--- a/run-container.sh
+++ b/run-container.sh
@@ -19,6 +19,7 @@ function main
     CONTAINER_NAME=vasl-templates
     DETACH=
     NO_BUILD=
+    BUILD_ARGS=
     BUILD_NETWORK=
     RUN_NETWORK=
     CONTROL_TESTS_PORT=
@@ -30,7 +31,7 @@ function main
         print_help
         exit 0
     fi
-    params="$(getopt -o p:v:e:k:t:d -l port:,control-tests-port:,vassal:,vasl:,vasl-extensions:,boards:,chapter-h:,template-pack:,user-files:,tag:,name:,detach,no-build,build-network:,run-network:,test-data-vassal:,test-data-vasl-mods:,help --name "$0" -- "$@")"
+    params="$(getopt -o p:v:e:k:t:d -l port:,control-tests-port:,vassal:,vasl:,vasl-extensions:,boards:,chapter-h:,template-pack:,user-files:,tag:,name:,detach,no-build,build-arg:,build-network:,run-network:,test-data-vassal:,test-data-vasl-mods:,help --name "$0" -- "$@")"
     if [ $? -ne 0 ]; then exit 1; fi
     eval set -- "$params"
     while true; do
@@ -71,6 +72,9 @@ function main
             --no-build )
                 NO_BUILD=1
                 shift 1 ;;
+            --build-arg )
+                BUILD_ARGS="$BUILD_ARGS --build-arg $2"
+                shift 2 ;;
             --build-network )
                 # FUDGE! We sometimes can't get out to the internet from the container (DNS problems) using the default
                 # "bridge" network, so we offer the option of using an alternate network (e.g. "host").
@@ -187,7 +191,7 @@ function main
 
     # check if testing has been enabled
     if [ -n "$CONTROL_TESTS_PORT" ]; then
-        CONTROL_TESTS_PORT_BUILD="--build-arg CONTROL_TESTS_PORT=$CONTROL_TESTS_PORT"
+        BUILD_ARGS="$BUILD_ARGS --build-arg CONTROL_TESTS_PORT=$CONTROL_TESTS_PORT"
         CONTROL_TESTS_PORT_RUN="--env CONTROL_TESTS_PORT=$CONTROL_TESTS_PORT --publish $CONTROL_TESTS_PORT:$CONTROL_TESTS_PORT"
     fi
 
@@ -196,7 +200,7 @@ function main
         echo Building the \"$IMAGE_TAG\" image...
         docker build \
             --tag vasl-templates:$IMAGE_TAG \
-            $CONTROL_TESTS_PORT_BUILD \
+            $BUILD_ARGS \
             $BUILD_NETWORK \
             . 2>&1 \
           | sed -e 's/^/  /'