Image SEO Guide: Alt Text, File Names, Compression and Formats
How to make product, shop and service photos help your SEO: alt text that describes, sensible file names, WebP/AVIF compression and correct sizing.
SEO, AEO and GEO consultant · Technical SEO, local SEO and content strategy
Last reviewed November 9, 2026
SEO, AEO & GEO consultant based in Rangpur, Bangladesh. Technical SEO, local search and content strategy. Full bio →
Good image SEO does two jobs: it helps Google understand what each photo shows, and it keeps pages fast. Write descriptive alt text, use meaningful file names, compress images to modern formats and set their dimensions. Real photos of your shop, team and work also build trust in a way stock images cannot.
Alt text that actually helps
Example: instead of "seo rangpur best seo", write "Front of a pharmacy on Station Road, Rangpur, with its signboard".
- Describe what is in the image as you would to someone who cannot see it.
- Include the product or place name when it is genuinely shown.
- Keep it to a short sentence; do not stuff keywords.
- Use empty alt (alt="") for purely decorative images.
File names
Rename IMG_2045.jpg to something like cotton-panjabi-navy.webp before uploading. Use lowercase words separated by hyphens.
Compression and formats
- Use WebP or AVIF where your platform supports them.
- Resize to the largest size the layout actually shows — a 4000px phone photo is rarely needed.
- Aim for small files on product grids, since many visitors browse on mobile data.
- Check results in PageSpeed Insights.
Sizing and lazy loading
Layout jumps hurt the CLS score covered in Core Web Vitals.
- Set width and height so the page does not jump while loading.
- Lazy-load images below the first screen; load the main image straight away.
Place images near relevant text
Google uses surrounding text and captions to understand images. Put product photos next to the product description, not in an unrelated gallery.
Sources and limits
This is a practical guide based on public documentation and day-to-day SEO work. It reports no original dataset, guarantees no ranking, and gives no fixed timeline.
Frequently asked
Yes. It helps Google understand images and is essential for visitors using screen readers.
WebP is widely supported and usually much smaller than JPEG; AVIF can be smaller still where supported.
Every meaningful image should. Decorative images should use empty alt text so screen readers skip them.
They are not penalised, but real photos of your work and premises are more useful and more trustworthy.