// For the resource file upload - check that the file is a PDF under 1MB in size.
add_filter('cred_form_ajax_upload_validate','cred_filetype_size_validation',10,2);
function cred_filetype_size_validation($error_fields, $form_data)
{
    //field data are field values and errors
    list($fields,$errors)=$error_fields;
    //validate if specific form
    if ( ($form_data['id']==358) || ($form_data['id']==473) )
    {
        if(isset($fields['wpcf-images'])) {
          //Retrieve file type
          $file_type_uploaded=$fields['wpcf-images']['field_data']['type'];

          //Retrieve file size
          $file_size_uploaded=$fields['wpcf-images']['field_data']['size'];

          //check if featured image exists
          if ( ($file_size_uploaded > 1000000) || ($file_type_uploaded != 'png') )
          {
            //set error message for featured image
            $errors['Resource File'] = 'Sorry the file you have uploaded is not of correct type (png) or exceeded 1MB limit';
          }
        }
    }
    //return result
    return array($fields,$errors);
}