detect when a file has been recorded in the pc

Hello Experts,
Our customer has this other software that takes and stores radiographies. We spoke with the software company who built it in eu but they are not interested in developing an interface or a feature to connect with our software.
We have noticed this particular imaging application stores its images in specific folders one per patient.
We started reading this folders and making copies of the images in order to upload them to our app....
Works just fine... but.....
There are too many images... and our customer continues making more....
although we copied all images its becoming harder to find the latest image stored.
 we do not want to remove alredy copied images .... so
is there any feature or finction that can detect the latest file stored in a hard disk ?
Like if we can get the list of files recently stored it wil be really fast to identify if the file is an image of our interest or not.
and much faster than reading the three thousand folders and many images inside each folder to see if there is a new image...

Or maybe I need to think out of the box? please your help
Regards,