Suggest an editImprove this articleRefine the answer for “Why are images a major cause of slow loading?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**Images** are one of the main causes of slow site loading: they weigh the most, block rendering, cause layout shifts, and are rarely optimized for format. **Key point:** minimize their size, defer loading (lazy), use modern formats, and specify dimensions, then they will stop slowing the site down.Shown above the full answer for quick recall.Answer (EN)Image**Images are one of the main reasons for slow site loading**, because they: --- ### 1. **Are the heaviest resources** They take up 60-80% of a page's total weight. One uncompressed 500 KB banner can weigh more than all the rest of the HTML, CSS, and JS combined. --- ### 2. **Load before rendering** If images sit at the top of the page, the browser tries to load them before showing content. This blocks rendering and increases LCP and FCP. --- ### 3. **Can cause layout shift** If an image has no width/height set, it loads later and pushes content around: this raises CLS (Cumulative Layout Shift), hurting perceived quality and SEO. --- ### 4. **Drain traffic and battery** Especially critical for mobile users. Large images mean slower loading, more battery drain, and wasted mobile data. --- ### 5. **Are not optimized for format** Using old formats (JPEG, PNG) instead of modern ones (WebP, AVIF) is another cause of excess weight. The same visually identical file can weigh three times as much. --- **Conclusion:** Images look great, but without optimization they turn into dead weight. Minimize their size, defer loading (`lazy`), use modern formats, and specify dimensions, then they will stop slowing the site down.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.