Customise The FTP File Name That Dahua Or Hikvision Sends For Still Pictures

Is there anyway that you can customise the name of the FTP files that a Dahua or Hikvision DVR sends?

Problem is this: customer has multiple sites in different locations. To get an overview of operations every five minutes a still is uploaded via FTP to their server, of a certain name ie: localyard.jpg, and overwrites the existing image, and therefore updates the website with the newest image.

The problem, unless I am missing something, is that when both the Dahua and Hikvision recorders (both NVR and DVR) send an image via FTP, the file names are by the date and time, so are always different so that the FTP folder would quickly become cluttered.

Is there a way that I can change so that each file FTP'ed has the same name?

Any help would be much appreciated.

I don't know about the DVR end, but this seems like something that would be simpler to do at the FTP server end via scripting. I'm not a programmer, but I do know that something like this should be a simple fix on the server end, where custom firmware on the DVR end is less likely.