Hi Elaheh,

I think it depends of the field you are in, but I know in biology it helps a lot to have visual elements such as schematics as much as possible, and of course the figures displaying your data. When writing your thesis you should think about the people who will read it, sometimes an image is worth a thousand words.  If you think you have too many visuals, usually you can add an appendix to your thesis (check whether this is ok to do in your case before adding an appendix). To have an idea of how many visuals is considered acceptable, the best would be to consult with your thesis advisor, and have a look at past theses in your field that were approved by your University. Good luck! Jean