Conditional Formatter

{ "rules_change_image_style_when_out_of_stock" : {
    "LABEL" : "Change image style when out of stock",
    "PLUGIN" : "reaction rule",
    "REQUIRES" : [ "rules", "ffc" ],
    "ON" : [ "field_is_rendered" ],
    "IF" : [
      { "data_is" : {
          "data" : [ "commerce-product:commerce-stock" ],
          "op" : "\u003C",
          "value" : "1"
        }
      }
    ],
    "DO" : [
      { "ffc_rules_change_image_style" : {
          "ffc_element" : [ "" ],
          "ffc_field" : [ "" ],
          "ffc_empty" : "outofstock"
        }
      }
    ]
  }
}