Images in collums

I have been using many photos in 3 columns with a description link to the website I would like to present. However, I have been noticing that somehow I am now unable to add new photos to the right hand column. It was supposed to pop up a button where I would add but I can only do this on the other two columns. Any idea on how I can overcome it? https://altabrasileira.com.br/sapatos/