Same newsletter, different image rendering depending on the recipient? It is normal — every email client uses its own rendering engine.
Pro tip: always test rendering on Gmail, Outlook, Apple Mail and a mobile device before each send.
Main causes
| Cause | Effect |
|---|---|
| Images blocked by default | Outlook, older Gmail |
| Dark mode | Colours / backgrounds inverted |
| Gmail compression | Slight quality loss |
| Screen size | Responsive adaptation |
| Slow connection | Progressive loading |
Best practices for consistent rendering
- Image width < 600 px
- Weight < 200 KB per image
- Always set alt text
- Set explicit
widthandheight - JPG for photos, PNG for logos
- Avoid 100% image emails (keep at least 60% text)
Per-client behaviour
- Gmail: compresses, sometimes blocks images in fallback mode
- Outlook: Word engine, blocks images by default
- Apple Mail: faithful rendering, loads via iOS proxy
- Yahoo: generally faithful
More on the responsive newsletter page.
Design newsletters that look great everywhere. Start free with Mailpro and its multi-client editor.