How to optimise images for WordPress?

Table of Contents

Alright, this time properly. All the ways people actually optimise images in WordPress, from simplest to more hands-on. You don’t need all of them. You pick what fits how much effort you’re willing to put in.

Images are heavy. WordPress doesn’t stop you uploading massive ones. That’s the whole problem.

Method 1: Optimise images before uploading (most underrated method)

This is the cleanest way and costs nothing. And almost nobody does it.

Steps:

  1. Take the image

  2. Resize it on your computer

  3. Keep width between 1200–1600px for most uses

  4. Save it as JPG or WebP

  5. Rename it to something sensible

  6. Upload to WordPress

That alone can cut image size by 70–80%.

No plugin. No risk. No drama.

Cost:
€0

Honest truth:
If you do only this, your site is already faster than most Irish WordPress sites.

Method 2: WordPress built-in image sizes (people ignore this)

WordPress automatically creates multiple image sizes. You just need to use them properly.

Steps:

  1. Upload the image

  2. Insert it into a page

  3. Click the image

  4. On the right panel, choose Image Size

  5. Use “Large” or “Medium”, not “Full Size”

Full size is almost always a mistake.

Cost:
€0

Method 3: Image optimisation plugin (most common approach)

This is what most people end up doing.

Steps:

  1. Go to Plugins → Add New

  2. Search for an image optimisation plugin

  3. Install and activate

  4. Let it compress existing images

  5. Turn on automatic optimisation for new uploads

These plugins compress images without visible quality loss.

Cost:
Free plans exist
Paid plans usually €20–€40 per year

Reality check:
Free plans are fine until you upload loads of images. Then they quietly cap you.

Method 4: Convert images to WebP

WebP files are smaller. Plain and simple.

Steps:

  1. Use an optimisation plugin that supports WebP

  2. Enable WebP conversion

  3. Let the plugin serve WebP images automatically

WordPress supports WebP now, so this works without hacks.

Cost:
Often included in image plugins
Sometimes paid feature

Worth it?
Yes, especially for image-heavy sites.

Method 5: Lazy loading (already in WordPress, mostly)

Lazy loading means images load as people scroll. Less initial load, faster feel.

Steps:

  1. Upload images normally

  2. WordPress adds lazy loading automatically

  3. Don’t disable it unless you know why

If you use a cache or performance plugin, make sure it’s not clashing.

Cost:
€0

Method 6: Optimise images via caching / performance plugins

Some performance plugins handle images too.

Steps:

  1. Open your cache or performance plugin

  2. Enable image optimisation or lazy loading

  3. Clear cache

This is handy if you already pay for one plugin instead of five.

Cost:
Usually €40–€60 per year for the plugin

Method 7: Use a CDN (for bigger or busier sites)

This matters more once traffic picks up.

Steps:

  1. Sign up for a CDN

  2. Connect it to your WordPress site

  3. Let it serve images from nearby servers

This helps Irish visitors load images quicker, especially on mobile.

Cost:
Free tiers exist
Paid plans vary

Truth:
If your site is small, this is optional.

Method 8: Proper image formats (simple but ignored)

Use the right format.

JPG or WebP:
Photos, banners, blog images

PNG:
Logos or images needing transparency

SVG:
Icons and simple graphics only

Using PNG for photos is just wasting bandwidth.

Cost:
€0

Method 9: Clean up old uploads

WordPress never forgets an image.

Steps:

  1. Open Media Library

  2. Switch to list view

  3. Remove unused images

  4. Regenerate thumbnails if needed

This doesn’t speed up page load directly, but it keeps the site tidy and backups smaller.

Cost:
€0

What I’d actually do on a normal Irish site

Resize before upload
Use JPG or WebP
One image optimisation plugin
Don’t touch full-size images
Leave lazy loading alone

That’s it. Anything beyond that is only needed if the site is big or busy.

Image optimisation isn’t glamorous. Nobody thanks you for it. But when a site loads fast on a dodgy mobile signal or slow broadband, that’s when it quietly earns its keep.

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