public String transform(MavenProject project, String tag, Date now) {
                // In case the Maven property is also a placeholder, replace it as well
                if(isEmpty(tag) || tag.equals("%" + letter)) {
                    tag = project.getVersion();
                }
                return doTransform(tag, now);
            }
Property to lookup for image name which overwrites the calculated default, which is calculated
on the project version and depends whether it is a snapshot project or not.
Used with format modifier %v
src/main/java/io/fabric8/maven/docker/util/ImageNameFormatter.java