how can I get a snapshot.jpg

[ccontrolled]

I own an old YHS-113 without IR and did not succeed with the app's to install it but it works fine on fritz-smh-rtsp with vlc .
But I do not need rtsp, only a current picture in the browser for example at http://192.168.178.24/snapshot.jpg

Is there any possibility to aktivate a jpg-snapshot in the system (how?) or do I have to complie an own firmware what would be too diffcult for me?
May be it would help to replace serverJ or serverM by any "imggrabber" ?