Looking for some help and advice with Flexbox

I’m trying to achieve this layout for my site where the thumbnails auto flow onto the next level as the breakpoints get smaller.

I’ve tried so many ideas - grids / layouter / just can’t seem to work it out…
Please help.

Hi Aidan. Have you been able to solve this issue? Normally layouters are flexible enough to make excess items flow to a new line once the box gets resized but I’ve had times when that’s not the case, let me know if you need help fixing it and we can take a look together