Anonymous below is correct: this is the one:
It is next to the garden.
Galata Tower is higher and at the other side (north) of the water, in another part of Istanbul.
Daniele is right that indeed many people put their pictures on the wrong location on the map.
Correct: the tower (and the walls) are those of the Topkapi Palace, as can also be seen clearly in my second link. At first glance the hill with the tower had seemed to me in the background.
The location: I don't immediately trust when I find a photo on the maps, I know that many upload them at random, but the ones I have indicated seem reliable. It is also true that Michael has already corrected me on other occasions: no problem :-)
Finally, before writing this comment I went back to the Bosphorus and I reported various errors to googlemaps: beautiful places in the mountains, the London bridge ...
Location is more to the north along Üsküdar Harem Sahil Yolu, or on the water.
That cannot be the Galata Tower. It is probably part of the Topkapi Palace. The picture is Sultanahmet. Aya Sophia and Blue Mosque.
Turkey, of course