FTP uses separate control and data channels, the stream you have shown is the control channel that sets up the data channel near the end with the line 227 Entering Passive Mode (192,168,19,225,243,129) which asks the client to make a connection to the server at IP 192.168.19.225 on port 243 * 256 + 129 which is 62337. If you have captured that stream (it will be from a random port on the client) with a filter ip.addr == 192.168.19.225 and tcp.port == 62337 then you should be able to save that stream as a jpg.