Based more on what I've seen in cats (rather than only on the picture - and maybe people aren't supposed to base guesses/takes on more than just picture); but I think the cat is going upstairs.
Cats I've seen tend to bolt upstairs, but often do a little walking on each stair before hopping down to the next one. If they don't do too much of that they often do a kind of "modified that" (involving a smaller area of the stair) . They can be super adept and fast. I'm just not sure they walk straight down the way they most often go straight upstairs.
(Do cats even ever walk down the middle of a case? Maybe, but I'm not sure I've seen that. (BUT, is it even an actual staircase. Couldn't resist throwing in that possibility because the cat looks like it's "regular walking" to me. )
Of course, I pretty much assume I'm wrong as is often the case with these "image things".
It later occurred to me that cats I've seen go downstairs tend to cats I know and that mill around my feet - or else that skip a couple of stairs; so maybe SOME do descend less "erratically". Maybe I'll look that up some time - or not....