HTML Reference »
Syntax reference for the HTML language.
How can I align images in a grid using HTML? How can I create a table using HTML?
To align images in a precise grid layout, you might want to start from the following HTML snippet:
<table><tr><td>Row 1, Cell 1</td><td>Row 1, Cell 2</td></tr><tr><td>Row 2, Cell 1</td><td>Row 2, Cell 2</td></tr></table>
You should not attempt to use Squarespace's integrated "image alignment" options to create this sort of layout, as those options only specify image positioning with relation to text flowing down your page, not in relation to a grid.
You can find additional information on creating / styling tables here.