ios - How can I detect if a photo has already been imported to a photo album? -

I found an app that copies the screenshot from another device to an iOS device and gives them a photo album , [Code] [Elassette Library assetForURL] and [Elassette Group adasset] . But every time I do this, it adds a screenshot even though they have already been added, is there a way to know if I have imported an image before? I can not use the filename because the screenshots use a simple index that becomes incremental.