The Paired Photos method has been deprecated in v2018. The default MVS method has been proven to be more reliable but please contact Technical Support for information on how to re-enable the Pair Photos option.
When the Paired Photos method is selected, the tab is divided into three sections: the Information and Warnings section, the Photos section and the Settings section.
Note that this dialog is resizable vertically, which expands bot the upper Photos section and lower Settings section equally.