Google AMP (Accelerated Mobile Pages) has strict requirements for images — both in terms of dimensions (which must be declared) and file size (which must be minimal). AMP pages are designed to load in under one second on 4G connections, so poorly optimised images will cause your pages to fail AMP validation. At imgresizr.com, you can optimise images for AMP pages, completely free.
AMP Image Requirements
| Requirement | Specification |
|---|---|
| Tag used | <amp-img> not <img> |
| Width and height | Must be declared explicitly |
| File size | Target under 150KB |
| Format | WebP recommended (JPG/PNG accepted) |
| Responsive | layout="responsive" attribute required |
How to Optimise Images for AMP at imgresizr.com
Upload your image to imgresizr.com. AMP requires explicitly declared width and height in the HTML — so note the exact pixel dimensions before exporting. Use the Resize tool to set your target dimensions: hero images at 1200×675px, in-content images at 800×450px or narrower. Convert to WebP using the Convert tool — WebP images are 25–35% smaller than equivalent JPEG/PNG, which is critical for AMP's strict performance requirements. Use the Compress tool to target under 150KB per image — AMP pages fail Core Web Vitals if images are too large. Export noting the exact width and height values and declare these in your AMP HTML markup.
AMP Image Optimisation Tips
- Declare exact width and height in AMP HTML — AMP cannot handle dynamically sized images
- Use WebP as the primary format with JPEG fallback for older browsers
- Compress all AMP images aggressively — AMP pages are measured against 4G mobile speeds
- Use a CDN to serve AMP images — the Google AMP Cache will serve them automatically for search results
- Validate your AMP page at amphtml.validator.appspot.com after optimising images
Optimise images for Google AMP pages at the correct dimensions and file size, free at imgresizr.com.