2 way 0.1″ jumper sockets – which way up

The general convention is sockets for power sources, pins for loads.

The reason is that you can touch the conductor of a pin, so you don't want to have a voltage on it. Sockets are often designed to make it difficult to accidentally touch the conduuctor. Much less relevant now in the days of low voltages, but why not stick to a convention that was usefull back when a voltage could kill.

It looks like this is a normal board-mount DB-25 mounted to a unusually small board. The only other part on the board seems to be a header, which is what the jumper wires are connecting to.

This was probably done because the jumper wires you can easily get like that will be for .1" pitch, and the pins on the DB connector are a little off from that. Also, the DB pins don't stick out very far on normal thru hole parts.

The part that isn't clear from the picture is whether either connector was thru hole or surface mount. If the header was thru hole, you'd expect the pins to stick out the other side of the board a bit, but there doesn't seem to be space for that. On the other hand, from what little we can see in the picture, there don't appear to be SMD pads.