[ ] struct can come after the params declaration and can contain files
/*~struct~Image:
*
* @param Id
* @text Identifier
* @desc An identifier that uniquely designates a material. If omitted, the file name will become the identifier.
*
* @param FilePath
* @text File Path
* @desc The file path. Please specify the folder and file.
* @default
* @require 1
* @dir img/
* @type file
*/