customize picture size and aspect ratio in slider widget

Hi,
I am building a site with the vantage theme and i am also using pagebuilder the idea is to have a photo gallery i pretty much have it where i needed to be except for one small detail, the pictures that are in a vertical format display in full size, and this looks weird when the slider transitions from a horizontal to a vertical slide… I would like the picture to resize and keep the same aspect ratio as the horizontal pictures.
Any help please?

URL: http://www.antonioaragonr.com/