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# Fixing Background Images That Are Blurry on Mobile

# Mobile images look blurry? Increase the mobile image width.

If images look soft **only on mobile**, they’re likely used as **CSS background images**. Browsers don’t expose a reliable display size for backgrounds, so Adaptive can’t always pick the perfect size automatically.

## Quick fix (about 2 minutes)

1. Go to **WP Compress → Image Optimization**.
2. Under **Adaptive Images**, open **Resize by Incoming Device** (click the **gear** ⚙️).
3. Set **Minimum mobile image width** to **800 px**.  
4. Click **Save**, then clear any caches and hard-refresh the page.

| ✅ You can **leave the big “Exclude from Adaptive” field empty** — nothing is required there.

## Why this helps
* **CSS background images** don’t provide an intrinsic size, so Adaptive can’t reliably identify how large they’ll render on mobile.
* Setting a **minimum mobile width** ensures a sufficiently large variant is served, preventing blur while keeping files lean.
* **The default is 400px**, but for certain image aspect ratios larger may be required.

## Tips
* Start at **800 px**; raise gradually if a specific background still looks soft.
* Avoid setting it unnecessarily high to prevent excess mobile bandwidth.
* This setting **does not affect regular&#32;`<img>`&#32;tags** — it primarily helps **CSS backgrounds**.