public static boolean skipExistingImages() {
    return Boolean.getBoolean(SKIP_EXISTING_IMAGES);
  }
Gets whether or not to skip pushing tags to existing images. This is defined by the {@code
jib.skipExistingImages} system property.

@return {@code true} if Jib should skip pushing tags to existing images, {@code false} if not
jib-core/src/main/java/com/google/cloud/tools/jib/global/JibSystemProperties.java