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Image optimisation for Wix SEO
Module 4·Lesson 4 of 12·25 min read

Image optimisation: alt text, file names, WebP and compression

Images are one of the biggest performance drains on Wix sites, and they are also a ranking opportunity. This lesson shows you how to optimise every image for SEO, speed and accessibility.

What you will learn in this Wix SEO lesson

  • Writing descriptive alt text that helps rankings and accessibility
  • Naming image files correctly before upload
  • Converting images to WebP format before uploading to Wix
  • How Wix handles image compression automatically (and its limits)
  • Using the Wix Image Manager to audit existing images

Images are simultaneously one of the biggest SEO opportunities and one of the most common causes of poor performance on Wix sites. Optimising images correctly improves page speed, enables image search ranking, and supports accessibility, all of which Google values.

Writing Descriptive Alt Text

Alt text is the text description of an image. It serves two SEO purposes: it helps Google understand what the image shows (supporting relevance), and it improves accessibility for users with visual impairments (a trust and quality signal). Write alt text as a natural description of the image that includes the keyword where it genuinely fits.

Bad alt text:  "image1.jpg" or "photo" or keyword-stuffing
Good alt text: "Wix SEO audit results showing 300% organic traffic increase in 6 months"

File Naming Before Upload

Name your image files descriptively before uploading to Wix. Use hyphens to separate words, include the primary keyword, and keep it concise. "wix-seo-results-case-study.jpg" is dramatically better than "IMG_4821.jpg" as a signal to Google about what the image contains.

Compressing Images Before Upload

How to compress images before uploading to Wix

  1. 1Go to squoosh.app (Google's free image compression tool)
  2. 2Drag and drop your image into Squoosh
  3. 3On the right panel, select "WebP" as the output format
  4. 4Set quality to 80%, this is visually indistinguishable from 100% in most cases
  5. 5Download the compressed image and check the file size (aim for under 150KB for supporting images)
  6. 6Upload the compressed image to Wix Media Manager

Complete How-To Guide: Optimising Every Image on Your Wix Site

This step-by-step guide walks you through a complete image optimisation process for your Wix site. Follow every step to ensure all images have descriptive alt text, SEO-friendly file names, proper compression, and correct dimensions.

Follow these steps to optimise every image on your Wix site

  1. 1Audit all images on your Wix site by going through each page in the editor and noting images without alt text
  2. 2For each image write descriptive alt text that naturally describes what the image shows and includes relevant keywords where appropriate
  3. 3In the Wix editor click on each image then click Settings or the Alt Text field and enter your description
  4. 4Before uploading any new image rename the file with a descriptive keyword-rich name using hyphens instead of underscores or spaces
  5. 5Convert all new images to WebP format using squoosh.app before uploading to Wix
  6. 6Compress every image to under 200KB for above-the-fold images and under 100KB for below-the-fold images
  7. 7Set explicit width and height for every image in the Wix editor to prevent Cumulative Layout Shift
  8. 8For hero images and above-the-fold images ensure they are no wider than 1400px
  9. 9Enable lazy loading for all below-the-fold images in the Wix editor image settings
  10. 10Use the Wix Image Manager to review all uploaded images and identify any oversized files that need replacing
  11. 11Test your pages in PageSpeed Insights after optimisation and check that image-related warnings have been resolved
  12. 12Add image structured data for key images using schema markup if they are relevant for Google Image Search
  13. 13Set a process for all future uploads: rename, convert to WebP, compress, then upload

Final Checkpoint

Every image should have descriptive alt text, be in WebP format under 200KB, and have explicit dimensions. PageSpeed Insights should show no image-related warnings.

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Your Course Resources

11 downloadable PDFs -- checklists, templates, worksheets and your certificate

Course Progress0/561 lessons

Checklists

Wix SEO Audit ChecklistPDF

20-point site-wide audit covering technical, on-page, content and local SEO

On-Page SEO ChecklistPDF

37-point per-page checklist: titles, headings, content, images, links, schema

Technical SEO Deep-DivePDF

50-point technical audit: crawlability, Core Web Vitals, speed, security, Wix-specific

Local SEO Setup ChecklistPDF

42-point local checklist: Google Business Profile, NAP, citations, reviews, local links

Site Launch SEO ChecklistPDF

48-point pre-launch and post-launch guide for new Wix sites going live

Templates & Worksheets

Keyword Research TemplatePDF

Printable tracker with columns for volume, difficulty, intent, priority and notes

Monthly SEO Report TemplatePDF

Client-ready report covering traffic, rankings, technical health and action plan

Content Brief TemplatePDF

Plan every page: target keywords, outline, competitor analysis, internal links, CTAs

Backlink Outreach TrackerPDF

Campaign log with status tracking plus 3 proven outreach email templates

Competitor Analysis WorksheetPDF

14-metric comparison table, content gap analysis and SEO SWOT framework

Achievement

Certificate of CompletionLocked

Complete all lessons to unlock (0/561 done)

Lesson Tools

No part of this Wix SEO Course content may be reproduced, copied, or distributed without the written consent of Michael Andrews.

This lesson on Image optimisation: alt text, file names, WebP and compression is part of Module 4: On-Page SEO Optimisation for Wix in The Most Comprehensive Complete Wix SEO Course in the World (2026 Edition). It covers Wix SEO optimization (US) and optimisation (UK) strategies applicable to businesses in the United Kingdom, United States, Australia, Canada, New Zealand, Ireland and worldwide. Created by Michael Andrews, the UK's No.1 Wix SEO Expert with 14 years of hands-on experience, 750+ completed Wix SEO projects and 425+ verified five-star reviews. This is lesson 27 of 561 in the most affordable, most comprehensive Wix SEO training programme available in 2026.