Elegent Themes fancy box size issue

Hello,

I am fairly new to wordpress, i am working on making a portfolio site for myself. I am using a theme from elegent themes ‘Envisioned’ .

This theme has a featured slider at the home page and uses Fancy Box when clicking on the images, it also uses fancy box for the themes galleries. I want to make the size of the fancy box larger for my videos around 1280 x 720 if possible but cannot find out how to change the size of it. When it shows images they seem inconsistent sizes, one is a good size but the others are smaller even though the source image is the same size.

Fancy box is not installed as a plugin but written into the theme so i can’t go to the plugin settings to change anything.

Any solutions?

Cheers.