Putting two images side by side?

This sounds so simple yet I’ve spend half an hour online trying to work it out!

I’m creating a photo essay and for some of the photos I would like to put them side by side and FILL the space. I’ve tried using a two column table but the left side is huge and the right side ends up somewhere weird. Any ideas how I can do this easily?

Btw I’m not sure if it matter but I’m using responsive theme.