The front desk clerk asked them to send in some photos, and then they made flyers together and distributed them around the area.
(send是及物动词,可直接说send sth,难到这里send in表示往来/里发送,而send sth 指往外发送吗?所以此处不能用send some photos)
这里的 send in 是“动词+副词小品词”型短语动词,一起作及物动词用,意思是“交出”。