Hi,
Thanks for the report.
Please open the file "components/com_hikamarket/views/categorymarket/tmpl/form_image.php" and replace
$options = array(
	'classes' => array(
		'mainDiv' => 'hikamarket_main_image_div',
		'contentClass' => 'hikamarket_category_image'
	),
	'upload' => $upload,
	'gallery' => $upload,
	'text' => ($upload ? JText::_('HIKAM_CATEGORY_IMAGE_EMPTY_UPLOAD') : JText::_('HIKAM_CATEGORY_IMAGE_EMPTY')),
	'uploader' => array('category', 'category_image'),
	'vars' => array(
		'category_id' => $this->category->category_id,
		'file_type' => 'category'
	)
);into
$ajax = false;
if(!empty($this->upload_ajax))
	$ajax = true;
$options = array(
	'classes' => array(
		'mainDiv' => 'hikamarket_main_image_div',
		'contentClass' => 'hikamarket_category_image',
		'btn_add' => 'hikam_add_btn',
		'btn_upload' => 'hikam_upload_btn'
	),
	'upload' => $upload,
	'upload_base_url' => 'index.php?option=com_hikamarket&ctrl=upload',
	'gallery' => $upload,
	'text' => ($upload ? JText::_('HIKAM_CATEGORY_IMAGE_EMPTY_UPLOAD') : JText::_('HIKAM_CATEGORY_IMAGE_EMPTY')),
	'uploader' => array('category', 'category_image'),
	'vars' => array(
		'category_id' => $this->category->category_id,
		'file_type' => 'category'
	),
	'ajax' => $ajax
);It will fix the upload by forcing the right upload base and some other parameters.
This fix will be include in the next release.
Sorry for the inconvenient.
Regards,