User Defined Targets

Hello,

I am trying to implement something in which user can click an image and give audio for that image and whenever that particular image gets detected afterward the audio should play (audio that user has provided). So, the clicking an image which can act as a trackable can be done by user-defined targets but the issue is I am not able to figure out how to save that user-defined image target so it can be used for future like even if the user closes the app or turn off their phone even after that when they open the app and the app detects that image it should play that audio. I am not sure if this is possible or not because I have read on a few forums that you can't save UDT. 

So, any help would be appreciated.

Thanks.