Dinah - I have always worked on a Mac, but in my new job I took a couple of years ago, I work on a PC. I find I need to clear the cache a lot more on a PC for some reason.
Also, I use a lot of keyboard shortcuts as opposed to the drop-down menus, and what I do quite often is use "Control" and the "-" symbol and it reduces the page I'm working on. I use it all the time if I'm working in Illustrator or Photoshop to reduce or zoom into an object (Control +), but if I'm on a web page and do it, it reduces the size of the type in the window. If you use (Control +) on a PC, (Command +) on a Mac, it will change your point size.
I hope that works for you. We've had uploading issues to the gallery on and off since the site had a big upgrade a while back, so we sincerely apologize for that.
Another thing that developed after the upgrade was that you would only upload your image in the first window. Don't type anything else in - just browse, select and upload. Then another window comes up and that's where you enter all your information. One way or another, we'll get everyone fixed up!