Suddenly Photos won

I’m having the same problem as judysl. I routinely add photos to my blog posts and have never had any problem until yesterday. When I tried to “Add media files from your computer” I could choose the file and it would show that it was chosen, BUT when I go to upload it I get the message: “Failed to write file to disk.” I tried with other photos. I tried rebooting. I tried sleeping on it, i.e. waiting till the next morning, not falling asleep on top of my computer ?? I’ve been doing this for years and haven’t changed anything on my computer since it last worked. I’m not savvy enough to do the FTP thing that esmi suggested. I’m assuming that some kind of bug has crept into the system. Please help. My site is: https://www.SusanVogt.net/blog