www.wysiwygwebbuilder.com

Something like this

http://matrixsupply.ca/

Is there a tool that one could just tell how many columns, rows, size, space etc.

Basically like the options found in the photo gallery tools

Thanks

The specified website does not use a responsive/flexible grid, it's a just a static (absolute) layout.
But if you want to create a responsive/flexible layout then you can use:
- layout grid
- flex box
- flex grid

Related tutorial:
http://www.wysiwygwebbuilder.com/layout_modes.html

I would like to just setup a bunch of breakpoints and then tell the grid how many columns to use in each breakpoint. That is how I did it on mysnapsonline.com and works well for images.

I am endeavoring to build a navigation menu as appears on the index page of mysnapsonline.com but with perhaps 100 or more links. I really like the square tile menu that Microsoft uses on Windows 8 & 10 in tablet mode

This can be done with the flex grid.

For an overview of the available menu please see:
http://wysiwygwebbuilder.com/navigation.html

Yes I was able to but it seems that a FlexGrid will not be placed in the 'Content Place Holder' of a master-page.
At least I have not been able to get it to work with the master-page.

FlexGrid can be used in a flexible layout only.