Camera = mass and cost, the two additional things you don't want on a space mission. Plus, on a probe with such a limited lifetime, you want to maximize the amount of bandwidth going for the primary scientific data as opposed to things like pictures.
Nowadays though, cameras are a lot lighter and cheaper than they were when Galileo was designed. Might a gas giant entry probe have a camera now? We'll see, whenever one is made again...
First of all check your history about the previous space mission to the other planets. The Russia probe landed on Venus, and took a snap shot I believe during the late 1960's with a camera. Voyage one and two got massive shots of the solar system from 1977 on up till it left the kieper belt into deep space. Missions to mars took picture too. The moon had a probe take a close up before crashing into it. All of this in on the internet just look it up. They had a camera on board Galileo but due to the atmospheric conditions the signal was blocked by the ionization of the atmosphere. Radio communication has the same problem on earth at times. I was a radioman in the U.S. Navy and I had to know that about communications.