Image Optimization for Websites: WebP, Right Sizes and Free Tools

When we build websites for small businesses, one problem shows up in almost every project: the images are far too large. A 4-megabyte photo uploaded straight from a phone can add whole seconds to a page load — and a slow page drives away both customers and Google.

The good news: image optimization doesn't require Photoshop or technical skills. This guide covers the three things that solve most of the problem: format, dimensions and compression.

Why image size matters so much

Google measures page speed with Core Web Vitals, and the most important metric — LCP (Largest Contentful Paint) — tracks how quickly the page's largest element loads. On most pages, that largest element is an image.

In practice:

• An LCP above 2.5 seconds hurts your search rankings
• Every extra second of load time measurably cuts conversions
• On mobile networks, heavy images hurt far more than on fast office Wi-Fi

1. Pick the right format

The rules of thumb in 2026:

Format	When to use it	Notes
WebP	Almost every image on a website	25–35% smaller than JPG at the same quality
JPG	Photos, when WebP isn't accepted	No transparency
PNG	Logos and graphics that need transparency	Large files for photos — avoid
AVIF	Early adopters — smallest files of all	Not yet supported everywhere

The single biggest win for most sites is converting JPG and PNG images to WebP. You can do it free in the browser with a PNG to WebP converter or a JPG to WebP converter — no signup, and you can convert up to 20 files in one batch.

2. Use the right dimensions

The other common mistake: uploading a 4000-pixel-wide image that's displayed at 800 pixels. The browser still downloads the whole giant file.

Good baseline dimensions:

Use	Recommended width
Hero/banner image	1600–1920 px
Content image in an article	800–1200 px
E-commerce product photo	1000–1600 px
Thumbnail	400 px

You can resize an image online without installing anything — the tool keeps the aspect ratio automatically and never upscales, so quality doesn't suffer.

3. Compress — but not too much

For WebP and JPG conversions, a quality setting of 80–88 is almost always right: the file size drops to a fraction while the difference stays invisible. Good targets:

• Hero image under 200 KB
• Regular content image under 100 KB
• Thumbnails under 30 KB

Pre-publish checklist

1. Convert to WebP — the biggest single saving
2. Size the image to its display size — don't let the browser shrink giants
3. Name files descriptively (office-oulu.webp, not IMG_4823.jpg) — a small SEO boost
4. Add alt text — accessibility and image search
5. Lazy-load below-the-fold images (loading="lazy")

Every tool on this checklist is free in one place: Listiq AI's free image tools — converters, a resizer and a background remover, with no signup and no watermarks. (Listiq AI is built by iibsofy, so we know the tools inside out — we use them in client projects ourselves.)

What if the whole site is slow?

Image optimization is the fastest single improvement, but if the site is heavy or outdated overall, a bigger rebuild can pay for itself quickly. We build fast, search-friendly websites for small businesses — get in touch and let's make your site fly.