Images are the most common cause of slow WordPress pages. A single large, uncompressed image can add seconds to your load time. Multiply that across a page with ten images and you have a site that most visitors will abandon before they see your content.
Image optimisation is not complicated, but it is frequently overlooked.
What image optimisation involves
- Compression — Reducing file size without a visible loss in quality. A 2MB photo can often be compressed to under 200KB with no noticeable difference to the viewer
- Correct dimensions — Uploading images at the size they will actually be displayed, rather than uploading a 4000px wide image for a 800px wide container
- Modern formats — WebP images are significantly smaller than JPEGs and PNGs at comparable quality. Most modern browsers support WebP and it should be the default for new uploads
- Lazy loading — Images below the fold (not immediately visible) load only when the visitor scrolls to them, rather than all at once when the page loads. This reduces initial load time significantly
How it affects your rankings
Large images are a primary cause of poor Core Web Vitals scores, particularly LCP (Largest Contentful Paint). If the main image on a page is slow to load, your LCP score suffers and your ranking potential drops with it.
Optimising images is one of the highest-impact, lowest-risk improvements most WordPress sites can make. A website checkup will show you how your images are currently performing and where the biggest gains are. Read more in our performance knowledge base.