I used a template and created a new page and I have a few pictures there. I can't seem to change the size. I am using the correct image code but it does not seem to have any affect. Any ideas?

First of all it would be very helpful to know
1/ which template?
2/ which framework?
,,,,,, Foundation
,,,,,, Bootstrap
,,,,,, Materialize
,,,,,, Framework less

That way we can be sure to give the correct advice based on the project you are working on