Frank Zhang, if you would like to display such kind of images like it shown at screenshot below, this is considered as custom code modification.
You will need to make changes for photo plugin and system plugins files.
Go to ow_plugins/photo/bol/photo_service.php file and find line:
CONST DIM_PREVIEW_HEIGHT = 400;
Change the value to 6000, for example.
Then go to ow_system_plugins/base/bol/attachment_service.php file and find line:
$dimensions = array('width' => 1000, 'height' => 1000);
Change the value 'height' => 1000 to 6000, for example.
After this go to Admin Area > Appearance > Edit Theme > CSS section and add the following code:
.ow_newsfeed_item_picture img {max-height:6000px !important;}
However you should remember that all your custom code modifications will be overwritten after update and you will need to make them again.