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4/4/20255 min readProUtility Editorial Team

The Ultimate Image Optimization Checklist for SEO (2026)

Don’t hit publish until you check this list. The 10 essential steps to ensure your images rank high and load fast.

You spend hours writing the perfect blog post. You spend days designing the layout. Then you upload a random image and hit "Publish."

Ideal for: Everyone publishing content on the web.

Stop.

TL;DR (Quick Checklist)

  1. Use WebP/AVIF
  2. Width matches container (Max 1920px)
  3. File size < 100KB (up to 200KB for large hero images)
  4. Lazy load images below fold
  5. Descriptive Alt Text

This checklist is part of our complete Image Optimization Guide for SEO.

Written by ProUtility Editorial Team Web performance & SEO tools used by developers and marketers worldwide.

Unoptimized images are one of the most common causes of poor website performance. Use this 10-point checklist for every single image you publish.

The 10-Point Checklist

Google recommends optimizing images for size, format, and loading behavior to improve performance and search visibility.

1. Format: Are you using Next-Gen?

  • YES: I am using WebP or AVIF.
  • NO: I am using PNG for a photo (Bad idea).

    Fix: Use our Image Converter.

2. Dimensions: Is it resized?

  • YES: The image width matches my container (e.g., 1200px or 800px).
  • NO: I am uploading a 4000px raw photo.

    Fix: Use our Image Resizer.

3. File Size: Is it lightweight?

  • YES: It is under 100KB (or 200KB for huge banners).
  • NO: It is 3MB+.

    Fix: Compress it immediately.

4. Filename: Is it descriptive?

  • YES: red-leather-sofa.webp
  • NO: IMG_88201.jpg

    Fix: Rename it before uploading.

5. Alt Text: Is it accessible?

  • YES: Describes the image accurately.
  • NO: It is blank or stuffed with keywords.

6. Responsive: Are you using Srcset?

  • YES: I serve different sizes for Mobile vs Desktop.
  • NO: I serve the desktop banner to mobile users.

7. Lazy Loading: Is it deferred?

  • YES: Images below the fold have loading="lazy".
  • NO: All images load at once.

8. LCP Check: Is the Hero eager?

  • YES: My top hero image is NOT lazy loaded.
  • NO: I am lazy loading my hero image (Hurts LCP).

9. Site Speed: Did you test it?

10. CDN: Is it global?

  • YES: I use a CDN (Cloudflare, AWS CloudFront, Vercel, or similar).
  • NO: I serve images from a single slow server.

Final Image Optimization Checklist (Copy/Paste)

  • Format: WebP/AVIF
  • Size: < 100KB
  • Width: Max 1920px
  • Name: descriptive-keywords.webp
  • Alt: Accessibility compliant

Conclusion

Print this out. Stick it on your wall. If you follow this checklist consistently, you significantly improve your chances of better SEO performance.

Start Optimizing Images Now

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Frequently Asked Questions

Why do I need a checklist?
It is easy to forget small steps like adding Alt Text or stripping EXIF data. A checklist ensures consistency and prevents SEO penalties.
What is the most important step?
Compression and Dimensions. These are the most important steps because oversized images slow page load speed, which directly affects Core Web Vitals and SEO.