Images make posts easier to read and can bring their own traffic from Google Images and visual search. Handled badly, they slow your pages, hurt Core Web Vitals, and can even get you a copyright claim. Image SEO is mostly a set of small habits you apply every time you upload. These are the 10 that matter in 2026, updated for modern formats (WebP and AVIF), lazy loading, and how Google now understands images.
1. Use Images You Have the Right to Use
Never copy images from Google search results; photographers and stock agencies actively send claims for unlicensed use. Use one of these instead:
- Free stock photos: Unsplash, Pexels, and Pixabay. See our list of royalty-free image sites.
- Your own graphics: Canva makes featured images, charts, and infographics easy without design skills.
- Screenshots: the most useful images in tutorials. Snagit and PicPick are good tools; see our screenshot tools list.
- AI-generated images: fine for illustrations, but label them honestly and never use them to fake product photos or results.
Original images (your own photos, screenshots, and charts) are a strong signal of first-hand experience, which helps both Google rankings and reader trust.
2. Choose the Right Format
- WebP: the default for the web now. 25 to 35 percent smaller than JPEG at the same quality, supports transparency, and works in all modern browsers. WordPress can generate WebP versions automatically.
- AVIF: even smaller than WebP, supported by current browsers and WordPress. Good for large photos.
- JPEG: fine for photos if you cannot use WebP.
- PNG: for logos, icons, and screenshots that need sharp text or transparency (or use WebP lossless).
- SVG: for logos and icons; tiny and sharp at any size.
- GIF: avoid for animations; a short MP4 or WebP animation is far smaller.
3. Resize Before You Upload
A 4000-pixel photo in a 800-pixel content column wastes megabytes. Resize to about twice your content width (for sharp display on high-resolution screens), typically 1200 to 1600 pixels wide. WordPress then creates smaller sizes and serves the right one to each device through responsive srcset images automatically.
4. Compress Every Image
Compression cuts file size by 50 to 80 percent with no visible difference. Use an online tool before uploading (see our online image optimizer tools), or let a plugin do it on upload and convert to WebP or AVIF: ShortPixel, Imagify, EWWW, or Smush. Aim for most in-post images under 100 KB.
5. Use Descriptive File Names
Rename IMG_0042.jpg before uploading. Use a few real words separated by hyphens that describe the image: homemade-sourdough-bread-crumb.jpg, not bread.jpg or sourdoughbread.jpg. Google uses file names as a small clue to what the image shows.
6. Write Useful Alt Text
Alt text describes the image for people using screen readers and for search engines, and shows if the image fails to load. Describe what the image shows and why it is there, in a short sentence. Include your keyword only where it describes the image naturally; stuffing keywords into alt text helps nobody. Skip alt text (leave it empty) for purely decorative images. WordPress shows the alt text field when you select an image; see how to add alt text in WordPress.
7. Put Images Near Relevant Text and Use Captions
Google uses the text around an image, the heading above it, and the caption to understand it. Place images next to the paragraph they illustrate. Captions are read more than body text, so use them where they add information, such as explaining a screenshot or a chart.
8. Lazy Load, but Not the Hero Image
WordPress lazy-loads images below the fold automatically, so they only download when the reader scrolls to them. The exception is the largest image at the top of the page (often the featured image), which is usually your Largest Contentful Paint element. It should load immediately: WordPress marks the first large image with high fetch priority automatically in recent versions, but check that your theme or optimization plugin is not lazy-loading it, as that slows LCP.
9. Set Social Sharing Images
When a post is shared, networks show the Open Graph image. Set it in your SEO plugin (Rank Math, Yoast, or AIOSEO) for each post. A 1200 by 630 pixel image works for Facebook, LinkedIn, X, and most messaging apps; Pinterest favors tall 1000 by 1500 pixel pins. More in optimizing posts for social media.
10. Make Sure Google Can Find Your Images
Rank Math, Yoast, and AIOSEO include images in your XML sitemap automatically, so a separate image sitemap plugin is no longer needed. Submit your sitemap in Search Console, do not block /wp-content/uploads/ in robots.txt, and use real img elements rather than CSS backgrounds for images you want indexed. Add structured data (Recipe, Product, HowTo) where it applies, which can show your images in rich results.
Image SEO Checklist
- Licensed or original image
- WebP or AVIF format
- Resized to about 1200 to 1600 px wide
- Compressed (most under 100 KB)
- Descriptive, hyphenated file name
- Helpful alt text
- Placed near relevant text, caption where useful
- Hero image not lazy-loaded
- Social image set in SEO plugin
- Included in the XML sitemap
For the rest of the page, follow our on-page SEO checklist.
Frequently Asked Questions
Does alt text help SEO?
Yes, mainly for Google Images and accessibility. It is one of several signals (file name, surrounding text, page topic) Google uses to understand an image.
Should I convert all images to WebP?
Yes, if possible. Optimization plugins convert existing images in bulk and serve WebP or AVIF to browsers that support them, with JPEG or PNG as a fallback.
How many images should a blog post have?
As many as help the reader: typically one every 300 to 500 words for tutorials and roundups. Every image should explain or show something, not just decorate.
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