Imagify

This is the case where the licence is not an extra: it is the product

Worth starting here because Imagify works differently from almost everything else, and it is the difference that decides whether it suits you.

In most plugins, the code does the work on your server. You can have it running and the licence gives you updates and support, which are separate services.

Imagify does not compress on your server. It sends each image to Imagify's servers, they process it there and send back the lighter version. The plugin is the messenger, not the machine. Without a key validating against their service there is no compression of any kind, because the work happens outside your site.

Put another way: here you are not buying updates, you are buying a processing quota.

What the official licence covers

The processing quota on their servers, which is what allows compression at all; the updates from the admin and the maker's support. The GPLClub team leaves the key activated on your site.

It pays most on sites that live off images: shops with a large catalogue, publications, portfolios and any site where photographs get uploaded every week. And it usually travels accompanied: the piece that performs alongside is WP Rocket, from the same maker, which members have in the catalogue. Images are half a site's weight; the other half is how everything else gets served.

What it does

• Compresses with an algorithm balancing weight and quality, at several levels of aggressiveness.
• Resizes to whatever maximum you set, which is where the largest saving comes from.
• Converts to modern formats such as WebP and AVIF, serving them to browsers that support them.
• Processes the whole library at once, as well as new images on upload.

The big saving is not where people think

Plenty gets said about the compression percentage and what genuinely changes a page's weight gets overlooked.

Resizing beats compressing. A modern phone photograph arrives four thousand pixels wide, and your site displays it at twelve hundred. The browser downloads all four thousand anyway. Setting a sensible maximum width reduces weight far more than any quality setting, and it does not show.

Modern formats beat the aggressive setting. Converting to WebP or AVIF usually gives a better result than squeezing the JPEG until the grain shows.

Two warnings that save frights: keep a copy of the originals before processing the whole library, because lossy compression does not undo; and be patient with the first pass over a large library, which takes time because each image travels out and back.

About licensing and the GPL

The plugin's code is distributed under the GPL and its use is free. The compression service behind it is another matter, contracted with the maker, and without it the plugin has nothing to do. They are not the same, and here the difference is larger than with other products because the work happens off your server.