What expression do you see?

This is more challenging because we don’t have the whole face.

In this picture, we have oblique eyebrows which are suggestive of sadness and/or stress.

When we look for other indicators of sadness, we can see a slight gloss and redness to the eye, which could be suggestive of tears and sadness, but dry hot weather and searing sun could create the same effect on the eyes.

There is clearly tension in the mans face, neck and shoulders.

So the most we can say from this photo is that this person is likely stressed, and could be sad, but we cannot say sad for certain from this photo alone.