Very easy but is the only permission key for you to edit file. without adding variable in file upload,then it seams the file doen't belongs to you anymore
<'set_var_width>...<'/set_var_width>
<'set_var_height>...<'/set_var_height>
<'set_var_description>...<'/set_var_description>
<'set_var_meta_content>upload<'/set_var_meta_content>
<'set_var_meta_type>...<'/set_var_meta_type>