Images Are Usually the LCP Element
On most pages, the largest single element on screen is an image - a hero photo, a product shot, a banner. That makes it the Largest Contentful Paint element by default, which means it's usually the single biggest lever for the LCP score, for better or worse.
A 4MB photo exported straight from a camera or a stock library doesn't announce itself as a problem. It just quietly adds a second or two to the moment a visitor sees something real on the page.
Format and Compression Do Most of the Work
Modern formats - WebP and AVIF - produce noticeably smaller files than JPEG or PNG at the same visual quality, often by 30 to 50 percent. Most platforms and browsers support them natively now, so there's rarely a reason to still ship JPEG as the primary format.
Compression level matters as much as format. A photo doesn't need to be lossless to look sharp on screen - most images hold up fine at 70 to 80 percent quality, and the difference is invisible at normal viewing distance while the file size drops substantially.
Serving the Right Size to the Right Device
The same image shouldn't be sent at the same size to every device. Responsive images - serving a smaller file to a phone screen and a larger one to a desktop monitor - cut a meaningful chunk of weight for the majority of visitors browsing on mobile.
Lazy loading helps everywhere except the one place it's tempting to apply it by default: the LCP image itself. Delaying the load of the very element Lighthouse is measuring makes the score worse, not better - it should load eagerly while everything further down the page waits.
Built In, Not Bolted On Afterward
None of this is a one-time fix - it's a set of defaults a project either has from the start or keeps fighting page by page. We covered the full picture of what a strong score actually requires in Optimizing a Webflow Website to Reach 95+ Lighthouse Performance.
If image weight is dragging a score down and it's not obvious where to start, get in touch and we'll walk through the fix.