Image guides

This page groups every guide we publish by the problem it solves, so you can start from a question rather than a list of titles. Each guide is written to answer one thing properly, with worked examples and real file sizes instead of vague advice.

If you already know what you need to do to a file, the tools directory is the faster route. If you are trying to decide what to do in the first place — which format to save in, how much compression is safe, what dimensions a banner should be — start here.

Formats

Which container to save an image in, what each format is actually good at, and when converting is worth the re-encode.

Compression

How lossy and lossless encoders reduce file size, what quality settings really change, and how far you can push them.

Sizing

Choosing pixel dimensions, resizing without distortion, and understanding the difference between resolution and dimensions.

Performance

How image weight affects load time, layout stability and the experience of people on slow connections.

SEO

Preparing images so search engines can read, index and rank the pages they appear on.

  • How to Optimize Images for SEO

    Filenames, alt text, structured markup and loading behaviour: what genuinely helps images get found and what does not.

    February 16, 2026 · 7 min read

Where to start

If you are new to image optimisation, read the format comparison first, then the compression guide. Those two cover most of the decisions that affect file size. Sizing and performance guides are worth reading once you are publishing images regularly on a website.

Every guide links to the relevant tool, so you can apply what you read immediately. All processing happens in your browser, so you can test settings on a real file without uploading anything.

New articles are added to the blog and indexed here automatically.