I don't remember seeing an add to dictionary in older versions. The current documentation doesn't seem to have dictionary updates listed:
I'm sure it is possible to remove the dimensions box on the upload form, or default them to blank, but it would require hand coding that I haven't done personally. I did a google search and found a few threads that discuss this like:
If you aren't successful on your own, this is something I could do for you in a premier support ticket.