Hello,
By quibbling I found the right image.
But don't ask how ...
The correct settings for me, for Camera : Dlink DCS-5020L :
Source Type : Ffmpeg
Source Path : http://mylogin:myPW@myIP:myPort/video/mjpg.cgi
Method : HTTP Tunnel
Target colorspace : 32 bit color
Capture resolution : 640x480