The viral picture showing the colors of the Palestinian flag lit on the Cairo Tower is a morphed one.
However, upon reverse image search, we found the image of Cairo Tower on Wikimedia Commons, the photo credited to Ahmedsantos. It features a violet color light, unlike the viral image. Further, we found the viral image in a blog post of Bulb America, an online bulb retailer. The blog mentions that the tower was adorned with LED lights upon request by the Egyptian government.
Thus it seems the viral image has been doctored to spread misinformation.