Why aren't my images mobile friendly?

Site URL: https://www.josecolorado.com/blog/cebl-nblc-canada-basketball-player-salaries

Whenever I take a screen shot of an image and put it into an "image block" on Squarespace it makes it becomes very small and unreadable on mobile. 

On desktop it is fine but on mobile it is way too small. 

Is there anyway to enlarge the image while not cropping off the content?

Thank you!