WP Smush Pro

The fastest image is the one that never downloads

It is what to understand before discussing compression percentages, because it changes where the effort belongs.

Everybody starts the same way: compressing. And that is fine, it removes weight. But on a page with thirty images, the visitor sees only three before deciding whether to stay. The other twenty-seven downloaded anyway, consumed their connection and delayed the moment the page became usable.

The big gain is not each image weighing thirty per cent less. It is not requesting the ones nobody will look at, and not serving a three thousand pixel photograph into a four hundred pixel space.

WP Smush Pro compresses, and additionally brings the two pieces that attack that.

What it brings

• Unlimited compression, applied to the whole library in one click and automatically to whatever you upload later.
• Advanced compression, reducing weight considerably more than the basic mode without it showing.
• A backup of the originals, optional, which is the feature that prevents regret.
• Lazy loading, so images get requested when the visitor reaches them.

The backup of the originals is not a detail

It is the difference between a reversible operation and one that is not, and it belongs decided before launching the first pass.

Lossy compression does not undo. Once the library has been processed, the quality that has gone does not come back. And there are two moments where that hurts: when you want to reprint a product photograph in a catalogue, and when you migrate the catalogue to another platform and discover your master images were the website's ones.

Keeping the originals takes space, which is why plenty of people disable it to save. It is a saving that costs. Enabling it, or copying the uploads folder before starting, makes the problem disappear.

What to do before compressing anything

Set a maximum upload width. It is the measure that removes the most weight of all and the one hardly anybody takes. A modern phone takes photographs four thousand pixels wide; your site displays them at twelve hundred. Trimming on upload saves more than any quality setting, and it does not show.

Check who uploads images. In a shop with several people loading products, or on a site where users upload content, the problem is not compression: it is that enormous files come in every day.

Check lazy loading at the top of the page. Deferring the main image, the one visible on arrival, worsens perceived speed rather than improving it. That particular one must load immediately.

Requirements

It needs WordPress. The first pass over a large library consumes resources and takes time, so it is worth launching at quiet hours and with a recent backup.

Alternatives in the catalogue

Images are half a site's weight; the other half is how everything else gets served, and WP Rocket handles that with caching, delivery and resource deferral. The two pieces get used together and it is the combination that shows most.

If the problem is not weight but the server, which is what happens in shops with big catalogues, Object Cache Pro works the database and W3 Total Cache the general caching.

If you are building a shop from scratch and speed is the priority, start with the theme rather than the plugins: Shoptimizer begins from a light base and that saves compensating later. And if you prefer a minimalist base theme, Astra Pro or Blocksy.

To know whether any of it helped, MonsterInsights brings the reports into the admin, although the honest measurement happens on a phone using mobile data rather than fibre.

Frequently asked questions

What removes more weight, compressing or resizing?
Resizing, by a distance. Setting a maximum upload width saves more than any quality setting.

Can the originals be recovered?
Only if you enable the backup. Lossy compression does not undo.

Should every image be lazy loaded?
No. The main one, visible on arrival, has to load immediately or you worsen the sense of speed.

Does it compress what I upload later?
Yes, it applies the same optimisation automatically to new images.

Does it replace a caching plugin?
No. They are two halves of the same problem and get used together.

How long does the first pass take?
On large libraries, a while and with resource use. Worth launching at quiet hours.