WebP Converter.
A Mac app that bulk-converts PNG, JPG, GIF, and other images to WebP. All processing is local — and your site gets measurably faster.
Contents
- What is WebP
- Why WebP now — the Core Web Vitals lens
- Why WebP Converter.
- Key features
- Supported formats
- Who is it for
- FAQ
What is WebP
WebP is an image format Google announced in 2010. Built on top of techniques from the VP8 video codec, WebP unifies lossy, lossless, alpha (transparency), and animationinto a single format.
That's a fundamental shift from a web that has, for decades, mixed JPEG (photos), PNG (transparency), and GIF (animation) depending on the use case.
Compression in numbers
Per Google's data and a long line of empirical studies, WebP delivers the following at equivalent visual quality.
| Compared to | WebP reduction (typical) | Bonus |
|---|---|---|
| JPEG (lossy) | ~25–35% | Adds transparency support |
| PNG (lossless) | ~26% | Keeps transparency intact |
| GIF (animation) | Significant savings + full color | Removes the 256-color limit |
"30% reduction per image" sounds modest in isolation, but on an article page with dozens of images that translates into hundreds of kilobytes — even megabytes — and a directly perceivable speed difference on mobile.
Browser support
With Safari 14 (2020), WebP became available in every modern browser. Chrome, Firefox, Safari, Edge, iOS Safari, and Android Chrome all support it natively today. "We can't ship WebP because some users don't support it" is no longer a valid reason to delay.
Why WebP now
In 2021, Google adopted Core Web Vitals as a ranking signal.Largest Contentful Paint (LCP) measures how long it takes for the largest piece of content on the page to appear, and on most article pages that "largest content" is the hero image.
Cutting image weight by 30% means cutting LCP by roughly the same amount, which in turn improves search rankings. WebP migration has graduated from "nice to have" to "fall behind your competition if you don't."
Server cost & CDN bandwidth
Smaller images affect not just user experience but operational cost. CloudFront, Fastly, and most CDNs bill per byte transferred. A 30% size reduction is a 30% reduction on your monthly invoice. For a mid-sized site moving 100 GB per month, that can be tens to hundreds of thousands of yen per year.
Why WebP Converter.
The benefits of WebP are obvious. The hard part is migrating the existing pile of images. WebP Converter. is designed to make that conversion both fast and safe.
1. Fully local processing
Images don't leave your Mac. Internal documents, unreleased work, and original assets are structurally safe — the app runs inside macOS's App Sandbox without network access.
2. Batch conversion
Drag and drop hundreds of images straight from Finder. You can also drop images from a web browser directly into the app.
3. Fine-grained quality control
Adjust lossy quality (0–100) or switch to lossless from the UI. Use quality 90 for hero images and quality 75 for thumbnails — the controls are yours.
4. EXIF preservation
Many online tools strip EXIF. WebP Converter. preserves capture metadata when you want it kept — essential for photo galleries and portfolio sites.
5. Watermarks
Burn in a logo or text alongside conversion. Useful for bloggers, photographers, and illustrators worried about theft.
6. Saved presets
Save conversion settings as presets ("Blog post", "Product shots", "Print"), and switch between workflows without reconfiguring every time.
Where each feature shines
WordPress / Next.js / Hugo image optimization
Drag your media folder into the app and write to a separate output folder to keep originals untouched while generating WebP versions. Pairs naturally with <picture> tags that fall back to JPEG/PNG.
E-commerce product images
For stores with thousands of SKUs, image optimization is enormous leverage. Save a preset like "Product (quality 80, 1920px, watermark)" and every new product can be normalized with a single drop.
Blog hero images
Article hero/thumbnail images directly drive LCP. Converting them to WebP at high quality often visibly raises Lighthouse scores.
Supported formats
| Direction | Formats |
|---|---|
| Read | HEIC, PNG, APNG, JPG, GIF, TIFF, DNG, EPS, PSD, JP2, J2K, JPC, BMP, JBIG, BIE, PNM, PGM, PBM, MAG |
| Write | WebP (primary). PNG / JPEG (in-app purchase). |
Who is it for
- Bloggers — boost Lighthouse scores by WebP-ifying past article images.
- Web developers / front-end engineers — ship optimized images alongside client deliverables.
- E-commerce operators — cut transfer costs and speed up product pages.
- Photographers / illustrators — make portfolio sites lighter.
- Marketing & comms — convert internal images without ever uploading them online.
FAQ
Q. Does WordPress support WebP out of the box?
WordPress 5.8+ supports WebP at a basic level, but it does not automatically replace existing JPEG/PNG with WebP. Migrating existing assets requires either manual work or a tool like this one.
Q. Lossy or lossless?
Use lossy (around quality 80) for photos and rich gradients. Use lossless for logos, screenshots, and line art with flat color regions. WebP Converter. lets you flip between the two with a single checkbox.
Q. Can it convert animated GIFs?
Yes. Animated GIFs convert to animated WebPs, generally with substantial size savings and full color.
Q. How is it different from Image Tool+?
Image Tool+ is the all-in-one app — multiple output formats, background removal, renaming, and more. WebP Converter. focuses on WebP and starts free. "I just want WebP" → WebP Converter. "I want one app to do everything" → Image Tool+.
Q. System requirements?
macOS 11 Big Sur or later. Universal Binary for both Apple Silicon and Intel.
Download
WebP Converter. is free to start. Add the features you need via in-app purchase or subscription.
Want to go even further? Try AVIF Converter.Or pick up the all-in-one Image Tool+.