Images must not be delivered larger than they are actually displayed to avoid loading unnecessary data.
Resizing images on browser side to reduce their rendering size is not recommended.
For instance, if your image is set to render at 300px by 300px on a particular page, don't upload the original 1000px by 1000px version of that image to your page. Instead, resize/crop the image to fit the display size and then upload it to your site to decrease the page weight and loading time.
Don't resize the following images: