I would like to inform that there are nuances to each email editor. For this new email editor, the columns chosen cannot be adjusted so we will need to adjust the content within.
The WIDTH of the images must be the same as well as the height (for the evenly distributed columns content field that you might be using). To fill in the white space, another option would be to use the background color of the row. You would just need to know the color code for your brand to fill in the color field.