La Conversione WebP Non Funziona? Problemi Comuni e Soluzioni

Introduction

WebP conversion usually works without issues. But when something goes wrong — blurry output, files that are not smaller, transparency problems — a few predictable causes explain most failures.

This guide provides a symptom-to-fix matrix for common WebP conversion problems. Find your issue, understand the likely cause, and apply the fix.

Quick Checklist: Before You Change Anything

Before troubleshooting settings, verify the basics:

• File size: Is your file under 10 MB? Larger files are rejected.
• Single file test: Try converting one file (not a batch) to isolate the issue.
• Browser support: Are you using a modern browser (Chrome, Firefox, Safari, Edge)? WebP encoding requires Canvas support.
• Import method: Did you import via URL or cloud? These use server routes and may behave differently than local files.

If the basics are fine, find your symptom below.

"My WebP is Bigger Than the Original"

This happens more often than you might expect, especially with PNGs.

Why it happens:

• The original PNG is already highly optimized (e.g., processed with pngquant)
• Lossless WebP can sometimes be larger than lossless PNG for simple images
• The image has few colors and hard edges — PNG's specialty

Fixes:

1. Try lossy at high quality (85-90): Even for graphics, high-quality lossy often produces smaller files than lossless.
2. Resize if dimensions are oversized: A 4000px image is large in any format.
3. Keep the PNG: If WebP is not smaller, there is no benefit to converting.

For more on mode selection, see lossy vs lossless WebP.

"The Output Looks Blurry / Has Artifacts"

Blurry or artifacted output is almost always a quality setting issue.

Why it happens:

• Quality slider set too low
• Lossy compression used on sharp graphics
• Image was upscaled (scaled up) before or during conversion

Fixes:

1. Increase quality: For photos, try 80-85. For graphics with text, try 90+ or lossless.
2. Use lossless for screenshots and text: Lossy compression blurs edges around text.
3. Do not upscale: Exporting at larger dimensions than the original creates blur. Export at original size or smaller.

For step-by-step guidance on photo quality, see our JPG to WebP guide.

"Transparency Looks Wrong" (Halos, Jagged Edges)

Transparent edges are the most fragile part of lossy conversion.

Why it happens:

• Lossy compression at medium/low quality introduces artifacts at transparency boundaries
• Incorrect background settings
• Color-to-transparent setting with wrong tolerance

Fixes:

1. Use lossless: Completely eliminates transparency artifacts.
2. Use high-quality lossy (90+): If lossless is too large, high quality minimizes edge issues.
3. Check background settings: Ensure background is set to transparent, not a fill color.
4. Test on contrasting backgrounds: View on white AND black to catch all halos.

For detailed transparency handling, see our PNG to WebP guide.

"Wrong Orientation" / "Image Rotated"

Photos from phones often have an EXIF orientation flag instead of actually rotated pixels.

Why it happens:

• The source image has EXIF orientation metadata
• Auto-orient setting is disabled
• Canvas export does not automatically apply EXIF rotation

Fixes:

1. Enable auto-orient: The converter has an auto-orient setting that applies EXIF rotation before export.
2. Re-export: With auto-orient enabled, convert again.

"Conversion Fails" (No Download, Errors)

Complete conversion failures are less common but can happen.

Why it happens:

• File exceeds 10 MB limit
• Browser does not support WebP encoding
• Corrupted or unusual source file
• Import route failed (URL/cloud imports)

Fixes:

1. Check file size: Must be under 10 MB.
2. Try a different browser: Chrome, Firefox, Safari (14+), and Edge all support WebP encoding.
3. Reduce dimensions: Extremely large images can cause memory issues.
4. Download locally first: If URL import fails, download the image to your device and upload directly.
5. Try a different file: If one file fails but others work, the source file may be corrupted.

For more on how conversion works, see the about page.

When Not to Convert

Sometimes the right answer is to keep your original format:

• WebP is not smaller: If the PNG or JPG is already optimal, converting adds no value.
• Quality cannot be maintained: If even high-quality lossy introduces unacceptable artifacts, keep the original.
• Compatibility requirements: If your pipeline requires JPG/PNG, do not force WebP.

For a broader perspective on format choices, see when to keep JPG/PNG.

Summary

Most WebP conversion issues come from:

• Mode/quality mismatches (wrong settings for the image type)
• Oversized dimensions (resize before optimizing)
• Transparency edge cases (use lossless or high quality)

The fix is usually simple: adjust quality, switch modes, or resize first. If conversion fails completely, check file size, try a different browser, or download URL sources locally.