Free Image Converter
Convert between JPG, PNG, WebP, and HEIC — instantly, in your browser. Nothing is uploaded anywhere.
Built for web developers shipping WebP assets, iPhone users stuck with HEIC files, and anyone who needs a different format without installing software.
How the conversion works
When you load an image, the browser decodes it into raw pixel data in memory. The tool then creates an off-screen <canvas> element, draws the decoded image onto it, and calls toBlob(type, quality) to re-encode the canvas data in the target format.
The resulting Blob is passed to a temporary download link and saved to your device. No data is written to any external location at any point.
HEIC files are a special case — browsers can't decode HEIC natively. The tool uses a WebAssembly decoder to read the HEIC container, extract the raw pixel data, and then hand that data to the Canvas API for re-encoding. The WebAssembly module runs locally; your file never leaves the browser.
Transparency is preserved when both input and output formats support alpha channels (PNG → WebP, WebP → PNG). Converting to JPG composites transparency against white, since JPG has no alpha support.
JPG, PNG, WebP, HEIC — when to use each
Format choice affects file size, quality, compatibility, and whether transparency survives. Here's the short version.
Compression: Lossy
Transparency: No
Typical size: 200–800 KB
Best for: Photographs, social media, email
The universal default. Every platform, browser, and app accepts it. Choose JPG when compatibility is your first priority.
Compression: Lossless
Transparency: Yes
Typical size: 100 KB–5 MB
Best for: Logos, UI assets, screenshots
Perfect pixel accuracy and alpha support. Large files — use it when quality or transparency matters more than file size.
Compression: Lossy or lossless
Transparency: Yes
Typical size: 50–400 KB
Best for: Web pages, Next.js / Nuxt apps
Google's modern format. Roughly 25–35% smaller than JPG at equivalent quality, with alpha support. All modern browsers support it.
Compression: Lossy
Transparency: No
Typical size: 1–4 MB
Best for: iPhone native captures
Efficient on-device but poorly supported elsewhere. Convert to JPG before sharing, uploading, or editing.
Common conversions — and what to watch for
Some format pairs are completely safe. One is worth avoiding.
| From | To | Why | Notes |
|---|---|---|---|
| JPG | WebP | Reduce file size for web use without visible quality loss | ✓ Safe |
| JPG | PNG | Need a lossless copy or want to edit without compounding artifacts | ✓ Safe |
| PNG | WebP | Smaller web delivery while keeping transparency | ✓ Safe |
| PNG | JPG | Maximum compatibility; transparency becomes white | ⚠ Loses alpha channel |
| HEIC | JPG | Universal compatibility for iPhone photos | ✓ Safe |
| WebP | PNG | Need a lossless editable version | ✓ Safe |
| JPG | JPG | Re-encoding at different quality | ⚠ Causes generation loss — avoid if possible |
Who converts images — and why
Format conversion sounds like a technical chore, but it comes up in a wide range of everyday workflows.
Web developers
Replacing JPG/PNG assets in a Next.js or Nuxt project
Convert all static images to WebP — typically cuts image payload 30–40% with no visual change
iPhone users
Trying to upload a photo to a form, CMS, or social site that rejects HEIC
Convert HEIC → JPG. Universal acceptance, no quality compromise at normal viewing sizes
Designers
Delivering a PNG logo to a developer who needs WebP for a landing page
PNG → WebP preserves transparency and halves the file size
Social media managers
Platform won't accept WebP or PNG; needs JPG under a size limit
Convert to JPG and adjust quality slider before downloading
E-commerce teams
Product photos from photographer arrive as TIFF/PNG at 10+ MB each
Convert to WebP for storefront, keep PNG master for retouching
4 things worth knowing before you convert
Most format mistakes are easy to avoid once you know the rules.
Always convert from your highest-quality source
If you have a RAW or TIFF original, export to PNG first, then convert from PNG. Starting from an already-compressed JPG and re-encoding adds visible artifacts that can't be undone.
WebP is safe for production in 2025
Safari added WebP support in version 14 (2020). Global browser support is now above 97%. You can confidently serve WebP without JPG fallbacks for most audiences.
Check transparency before converting to JPG
Logos, PNGs with drop shadows, and UI overlays often have transparent areas that aren't obvious until you export to JPG and see a white rectangle appear. Always preview before downloading.
HEIC is great on-device, awkward everywhere else
Apple's HEIC format compresses photos efficiently but isn't supported by most websites, CMSes, or Windows apps out of the box. Convert to JPG as soon as you move photos off an iPhone.
Lossy vs. lossless — what actually happens to your image
Lossy compression (JPG, lossy WebP)
Lossy formats discard pixel information the human eye is unlikely to notice — subtle color transitions, high-frequency detail in smooth gradients. The encoder makes a trade: smaller file for slightly reduced fidelity.
The problem with re-encoding lossy files is generation loss: each encode introduces a small amount of artifact. A JPG re-saved as JPG three times looks noticeably worse than the original. Always work from the highest-quality source and encode to lossy once, at the end of your workflow.
Lossless compression (PNG, lossless WebP)
Lossless formats compress the file without discarding any pixel data. Every pixel in the decoded image matches the original exactly. File sizes are larger, but you can encode, decode, and re-encode indefinitely with no quality loss.
PNG is the standard choice for lossless web assets. Lossless WebP is newer and produces smaller files than PNG for most images — worth using if you're building a performance-sensitive web app and your users are on modern browsers (which is nearly everyone in 2025).
Your files never leave your device
The conversion runs entirely in your browser's memory using the Canvas API. No upload request is made, no copy is stored, and the data is gone when you close the tab. Open DevTools and check the Network panel — you won't see any outgoing requests containing your image.
Common questions
How does converting to WebP help my website?
WebP files are typically 25–35% smaller than JPG at comparable quality, and support transparency like PNG. Smaller images load faster, which improves Core Web Vitals scores — particularly LCP (Largest Contentful Paint). All modern browsers support WebP, so there's no reason not to use it for new web projects.
Will I lose quality when converting?
It depends on the direction. PNG to WebP (lossless) or PNG to JPG are both safe starting points. The dangerous path is re-encoding an already-compressed JPG as another JPG — each encode adds artifacts. Always convert from the highest-quality version you have, and encode to a lossy format only once.
Can I keep transparency when converting?
Yes, if the output format supports it. PNG → WebP and WebP → PNG both preserve the alpha channel. Converting any transparent image to JPG fills transparent areas with white, because JPG has no alpha support.
Why won't my HEIC photo upload to websites?
HEIC is Apple's proprietary format, introduced with iOS 11. Most browsers, CMSes, and social platforms don't support it natively. Converting to JPG gives you a universally accepted file. On iPhone, you can also go to Settings → Camera → Formats → Most Compatible to shoot in JPG by default.
Is my image sent to any server?
No. The entire conversion happens in your browser using the Canvas API and (for HEIC) a local WebAssembly decoder. No network requests contain your image data. You can confirm this by opening DevTools → Network tab before converting.
What's the difference between PNG and lossless WebP?
Both are lossless, meaning decoded pixels are identical to the original. Lossless WebP typically compresses 20–30% better than PNG for photographs and mixed images. For images with large areas of flat color (logos, diagrams), the difference is smaller. If you're targeting modern browsers and want the smallest lossless file, use WebP.