MLS Photo Resizing Policy
This setting determines how the images will be adjusted when resizing them to fit the specified MLS dimension. Below you will see the difference between the options available when editing your tour. To find this setting go into your tour Info tab and scroll down to MLS Photo Resizing Policy.
Use Customer Settings
You also have the option to go into your Account Settings to set a default MLS Photo Resizing Policy that will be used every time a new tour is created.
Below is a picture with each setting used so you can see the difference and find the one that works best for you.