We get a pcap file which we open in WireShark. It comprises only 28 packets from only two different hosts - so this challenge should not be too difficult. Usually we would first navigate through the TCP streams via right-click on a TCP packet ->
TCP Stream to get an idea of what is (roughly) going on. Here we only need to scroll a little to see that a JPEG picture has been transferred (see screenshot below, grey row).
We probably could extract the picture manually, but WireShark already comes with the exact feature required here. Navigate to
Export Objects and select the only file available. Save it somewhere as .JPEG and enjoy the flag!