diff --git a/Jenkinsfile b/Jenkinsfile
index 6473968..0c0e031 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -20,7 +20,7 @@ pipeline {
             steps {
                 script {
                     sh 'echo "git.thisfro.ch/jenkinsci/pflaenzli:${BUILD_NUMBER}"'
-                    def numberTagImage = docker.image('git.thisfro.ch/jenkinsci/pflaenzli:${BUILD_NUMBER}')
+                    def numberTagImage = docker.image("git.thisfro.ch/jenkinsci/pflaenzli:${BUILD_NUMBER}")
                     docker.withRegistry('https://git.thisfro.ch', 'jenkins-ci') {
                         numberTagImage.push()
                     }