Image SEO: Making Every Image Work For You

Images are usually the heaviest files on a page and the least optimised — unnamed, uncompressed, undescribed. Fixing them pays three ways at once: faster pages (a ranking factor), accessibility for visually-impaired visitors, and a whole second search channel through Google Images.

Remember from Lesson 1.1: Google can’t “see” images the way humans do — during indexing it understands them through signals you provide: the file name, the alt text, the surrounding content, and structured data. Image SEO is simply providing those signals deliberately. Five practices cover essentially everything:

1. Descriptive File Names

The file name is the image’s first identifier — and cameras and WhatsApp produce the worst possible ones:

IMG_20260315_143022.jpg
WhatsApp Image 2026-03-15 at 2.31.44 PM.jpeg
final-final-2 (1).png

eggless-chocolate-photo-cake-pune.jpg
theme-cake-cricket-first-birthday.jpg
customised-cake-price-list-2026.png

The pattern: lowercase, hyphens between words, describing what the image actually shows — naturally including keywords when they genuinely describe the image. Rename before uploading; WordPress makes post-upload renaming painful.

2. Alt Text: Describe, Don’t Stuff

Alt text (the alt attribute) exists first for accessibility — screen readers speak it to visually-impaired visitors, and browsers show it when images fail to load. Google reads it for the same purpose: understanding what the image depicts. That dual purpose gives you the quality test: good alt text describes the image to someone who cannot see it.

alt="cake pune best cake eggless cake order cake online cake shop pune birthday cake"

alt="Two-tier eggless chocolate cake with cricket theme decorations for a first birthday"

The rules:

• One honest sentence, roughly 8–15 words. Keywords appear only when they truly describe the image.
• Skip “image of” / “photo of” — screen readers already announce it’s an image.
• Decorative images get empty alt (alt="") — background flourishes and dividers carry no information; empty alt tells screen readers to skip them.
• Images containing text (price lists, infographics) must have that information in alt text or nearby page text — Google and screen readers can’t reliably extract it from pixels.

3. Compression and Modern Formats

Image weight is the #1 cause of slow pages, and speed feeds Core Web Vitals (full treatment in Module 4). Three habits eliminate the problem:

1. Resize to display size before uploading. A 4000px camera photo displayed at 800px wastes 90%+ of its bytes. Resize to roughly the largest size it will display.
2. Use WebP. The modern format delivers the same visual quality at a fraction of JPG/PNG weight, with universal browser support. Free converters (Squoosh in the browser, or any bulk tool) handle it; many WordPress optimisation plugins convert automatically on upload.
3. Compress the rest of the way. Aim under ~150KB for content images, under ~250KB for full-width heroes. In practice: a well-compressed WebP at display size almost always lands there naturally.

4. Lazy Loading

Lazy loading defers off-screen images: the browser loads only what’s visible, fetching the rest as the visitor scrolls. Faster first paint, less wasted data — with one critical exception: never lazy-load the first visible image (your hero/featured image). Deferring it delays the page’s largest visible element — exactly what Core Web Vitals penalises. Modern WordPress applies lazy loading automatically and skips the first image; just don’t fight it with plugins that lazy-load everything indiscriminately.

5. Ranking in Google Images (The Forgotten Channel)

Google Images is one of the largest search engines in the world by itself — and for visual purchases (cakes, clothing, décor, jewellery, food), customers often search images first. Businesses with optimised original photos routinely win discovery there while their websites are still climbing the classic rankings.

What ranks in image search:

• Everything above — file names, alt text, compression are the core signals.
• Original photos. Stock images rank poorly (they exist on thousands of sites) and signal nothing about your actual work. Your real photos are unique content by definition — the same E-E-A-T logic from Lesson 1.2 in visual form.
• Relevant surrounding content: Google reads the text around an image — captions, the paragraph before and after, the page’s topic — to understand and rank it. An image on a well-optimised page (Lessons 3.1–3.4) inherits that page’s clarity.
• Image sitemaps: for image-heavy sites, an image sitemap tells Google about every image explicitly. WordPress SEO plugins (including Rank Math) typically include images in the sitemap automatically — verify it’s enabled and this is handled.