I mention on the front page that this site is "truly accessible". Here is a quick definition of a truly accessible web site:

• It is served over HTTP,
  ensuring compatibility with browsers that don't support the encryption schemes commonly required by modern HTTPS-only sites.

• It does not require JavaScript,
  ensuring compatibility with browsers that either don't support JavaScript or run it comparitively slowly.

• It uses rather basic CSS,
  ensuring compatibility with browsers that struggle with advanced CSS or don't support CSS 3.

• It does not use any custom fonts,
  ensuring compatibility with browsers that don't support them, as well as for users who don't use anti-aliasing.

• It does not have huge images,
  ensuring compatibility with low-memory systems.

As a web developer, you should ask yourself the following question:

Am I building a web application or a web page?

If you are building a web page, then you should strive to make it truly accessible.

Questions and answers

What if I want to share a really large image on my web page?

Then you should still use a smaller version of it on your page, but make it a direct link to the full-size image.
    Use the CSS rule a img { border: none; } to remove the border from the image-link.