Saving for Web
Generally, images should be less-than 1,000 kB in size (under 1 megabyte).
If you remember from your introductory design classes, creating and saving files for print is much different than for web. For example, printers print at 300 ppi, but screens only need 72 ppi for proper resolution. The larger your files, the longer it will take your page to load. And no one likes a slow-loading page.
To optimize images for the web, many image editors have a “Save for Web and Devices” or “Export As” in their save options. There, you can change image formats and sizes to try and get your files of an appropriate size.
Here is the original dog image, which clocks in at an enormous 23.9 mB, and 5597px by 3148px. Watch how long that loads in another tab.
In contrast the one you see below was optimized for web, sized and cropped to 1000px by 500px. It’s much more managble at 110 kB, and is hardly distinguishable from the original (at least on the web).