Limit dimensions
Though it may seem obvious, the easiest way to keep file size down is to limit the dimensions of your graphic. There aren’t any numerical guidelines here; just don’t make graphics larger than they need to be.
Scale down large images.
Crop out any extra space around the important areas of your image.
Avoid large graphics if they are not absolutely necessary.
Get Web Design in a Nutshell, 3rd Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.