Trouble Adding Photos

Whenever I try to add photos to a post I get an error message. I used to be able to switch to media library and the photos would be added there, but now that doesn’t happen. It’s all blank. I really am hating all the updates that wordpress has done lately because they have made everything worse and not better. I don’t like the way they have you customize your site when the template you already have is customizable and it has overridden the way I used to adjust my page with the size and everything. Can I go back to a previous version??