I don't do motion FTP but for my HikVision ANPR cameras, my receiving FTP server gets the complete .jpg within about 5 to 10 seconds of the capture time. But, as @Phil said, it will vary depending on various factors he already mentioned.
And of course the FTP server will see the file as soon as it starts receiving it, but it may not be completely written for another few milliseconds/seconds, so you have to be careful if you have some sort of automatic system to process or move the photos on the FTP server.
And of course the FTP server will see the file as soon as it starts receiving it, but it may not be completely written for another few milliseconds/seconds, so you have to be careful if you have some sort of automatic system to process or move the photos on the FTP server.
