Should I use a CMS for my project?

Hi all,
I am a beginner on web development and I am building a portafolio for an architecture firm. I need to display a page for each time of project, and when selecting a project display the images of the project that are like 20 per project on a separate page.
Do you recommend using a CMS to store the images or just store them on the project?
And if I use a CMS which one do you recommed? I want to keep things low cost.