How can you create a scattered div layout?

Hi, I’m trying to create a portfolio site similar to this homepage layout:
i.e. an image gallery that is collage rather than a grid layout.

I have tried using website builder: cargo (as that ref site does) but it’s quite limiting for custom code so ideally i’d like to build it afresh.

  • Are there tool that allow to design div positioning via drag and resizing rather than writing the code?
  • Is there a responsive CSS frame work that shrinks the images/divs proportionally like the ref website?