To magnify is to make something bigger, whether in size or in significance.
A magnifying glass makes things look bigger and when anything is magnified, it gets larger in some way. If your hunger is magnified, you've gotten hungrier. Wearing a heavy coat on a hot day will magnify the heat: you're feeling hotter and hotter. Also, non-physical things get magnified. The press could magnify a story by discussing it over and over, making it a bigger story than it was originally. All types of magnifying make things bigger.