I was trying to figure out if I could duplicate the message that you were getting to see if I could figure out how to help you avoid the message you are getting.
The good news i was able to get the message .
There are at least 3 ways to get to the point that you are actually adding a picture to your gallery. I did get the message you received several times when I used one of the methods. The one that seemed to avoid it in all cases was using the bulk picture upload even for single pictures.
However I did do a screen shot that may be part of the reason you are getting it.
I found that if I used any of the single picture upload options I received the screen below. If I hit "
add picture" without a minimum of information filled out the message you are getting popped up.
For some reason you must give the photo a title. (It did not used to require a title but it seems to as of the last several months/years)
Obviously you have to attach a photo.
The rest of the screen is superfluous and adds tot he confusion.
Since I always use the bulk picture upload page I had never seen the page below and it is potentially confusing I suppose.
I have put red boxes around the things you appear to have to fill in before you "add picture" button.