Set a maximum upload size for a Gravity Forms image field

Limit Gravity Forms Upload Size

function limit_file_upload_size( $validation_result ) {
	$form = $validation_result['form'];
	
	foreach( $form['fields'] as &$field ){

		// NOTE: Add a custom CSS class to your image upload field and grab onto it here...
        
		if( strpos( $field['cssClass'], 'choose-file' ) === false )
			continue;
		
		$is_hidden = RGFormsModel::is_field_hidden( $form, $field, array() );
		
		if( $is_hidden )
			continue;
		
		$input_name = 'input_' . $field['id'];
		$temp_filename = RGFormsModel::get_temp_filename($form['id'], $input_name);
		$temp_location = RGFormsModel::get_upload_path($form['id']) . '/tmp/' . $temp_filename['temp_filename'];

		if ( isset( $_FILES[$input_name] ) && !empty( $_FILES[$input_name] ) )
			$filesize = $_FILES[$input_name]['size'];
		elseif ( file_exists( $temp_location ) )
			$filesize = filesize( $temp_location );
		else
			continue;
        
		// NOTE: 75 = the max. KB size ...
        
		if ( $filesize > 75 * 1024 ) {
			$validation_result['is_valid'] = false;
			$field['failed_validation'] = true;
			$field['validation_message'] = 'Maximum logo file size cannot exceed 75 KB.';
			unset( RGFormsModel::$uploaded_files[$form['id']][$input_name], $_FILES[$input_name] );
				continue;
		}
    }
    
    $validation_result['form'] = $form;
    return $validation_result;
}
add_filter('gform_validation_[your form ID]', 'limit_file_upload_size');