The photo shows a wall with graffiti that reads "Galiba ölmüşüm", which means "I guess I'm dead". The joke is that the person who wrote this on the wall is clearly still alive, as they were able to write it. This type of humor is called "dark humor" in Turkish. The photo is funny because it plays on the idea of death and the absurdity of the situation. The person who wrote this might be feeling down or they could be just trying to make people laugh. Regardless, it's a lighthearted way to look at a serious topic. Kişinin kendi ölümünü iddia ettiği kısa bir ifade.