The photo shows a woman wearing a black polka dot dress. The dress is made of sheer material, and you can see her legs through it. The joke is that the woman is wearing a dress that is so sheer, it's almost like she's not wearing anything at all. This could be considered funny because it's a bit suggestive and could be interpreted as the woman trying to be sexy. Here's a possible joke in Turkish: "Bu elbiseyi giymiş ama giyinmemiş gibi. Tam bir şeffaflık abidesi." Translation: "She's wearing this dress, but it's like she's not wearing anything. A true monument of transparency."