In my opinion, it is perfectly fine if you want to put so many original pictures in your thesis and if you are writing a thesis in natural science, you can even put some pictures from other papers/books in your introduction chapter. Just try to imagine you are a thesis reader (a professor) with so many other things to do. They would like to read less text and see more comprehensive figures. Of course, making a figure comprehensive depends on the quality of your graphics as well as your caption text.
So here's what I suggest: anytime you want to put a figure in your text, ask yourself: how this figure is going to help my readers understand the main point? Is it conveying the main message? And how the captions will help to understand this message?
Remember, other people also have limited time and sometimes limited interest in what you did or even the task of evaluating the thesis, so it is up to you to make your material concisely so that they can understand about your intentions easily.