* - select: <select>
* - checkbox: <input type="checkbox">
* - multiselect: More a grid of checkboxes than <select multi>
- * - button: <input type="image"> if 'image' is set, otherwise <input type="submit">
- * (uses 'label' as button text)
+ * - button: <input type="submit"> (uses 'label' as button text)
* - hidden: Not visible to the user, but needs to be preserved for the next request
* - null: No widget, just display the 'label' message.
* - options: (array) Maps option values to Messages for the
* 'select' and 'multiselect' types.
* - value: (string) Value (for 'null' and 'hidden') or default value (for other types).
- * - image: (string) URL of an image to use in connection with the input
* - label: (Message) Text suitable for a label in an HTML form
* - help: (Message) Text suitable as a description of what the field is
* - optional: (bool) If set and truthy, the field may be left empty