Creating new images based on existing native website images

Hi, All!

I am trying to help my graphic designer understand how we can inherit the properties of the image they are replacing on the website. 

Is there some feature/tool that allows you to manage images/templates to conform to the assets that already exist on your website?

I hope this makes some sort of sense but typically I just analyze the properties of the file and try to mimic it but is there a simple way to import them to make them the same as the original image that we are replacing?

Thank you!!

Richard