Which theme will resize for differing screens ?

I currently have a Modularity Lite theme which was set up for me. My biggest gripe with my site is that it doesn’t resize for different screens. I use my site to portray my photographs, Modularity lite puts 5 images across the width of the screen which is fine on a 13” laptop, but of course on say an i-pad mini this won’t resize and looks obviously amateurish.
Therefore I wonder if anyone can suggest a theme that would resize for differing screens. I have to consider that this will probably be too complex for me to re-work myself so I wonder if anyone can advise how I would go about finding, and paying someone to do this for me.
I shall of course have to consider the costs and make the decision whether this is worth doing.

Many thanks in advance.