PNG to JPG, JPG to WebP: How to Convert Image Formats (and Which to Use)

"Convert this to a JPG." "Can you send it as a PNG?" "Why is my site slow — should I use WebP?" Image formats trip people up constantly, because each one is good at something different. This guide explains the three formats you'll actually meet, when to convert between them, and how to do it for free in your browser.

The three formats that matter

Ninety-nine per cent of everyday image work involves just three formats:

JPG (JPEG) — the workhorse for photographs. It uses lossy compression, meaning it discards some detail to achieve small file sizes. For photos, that trade-off is almost invisible and the size savings are huge. Its one big limitation: no transparency.

PNG — the choice for graphics, logos, screenshots, and anything with sharp edges or transparency. It's lossless (no quality loss) and supports transparent backgrounds, but files are much larger than JPG for photographic content.

WebP — the modern format that does both jobs. It supports transparency like PNG and compresses photos smaller than JPG at the same quality. Every current browser supports it, which is why it's now the default recommendation for the web.

When to convert — and to what

Here are the conversions people actually need, and why:

• PNG → JPG: You have a photo saved as a bulky PNG (common with screenshots and downloads) and want a smaller file. Converting to JPG can shrink it dramatically. Just remember transparency will be lost.
• JPG → PNG: Less common, but useful when you need a lossless copy to edit repeatedly, or a format that some older software prefers.
• Anything → WebP: You're putting images on a website and want the smallest files without visible quality loss. WebP is the win here.
• WebP → JPG/PNG: You downloaded a WebP and a program (or a colleague) won't accept it. Convert to the universally compatible JPG or PNG.

How to convert an image in your browser

1. Open the Image Converter.
2. Drop in your JPG, PNG, or WebP.
3. Choose the target format.
4. For JPG or WebP, set the quality; if you're converting a transparent image to JPG, pick a background colour to fill the transparent areas.
5. Download the converted file.

It all happens locally on a canvas in your browser — nothing is uploaded — so your images stay private and there's no server round trip.

The transparency gotcha

This is the single most common surprise: JPG cannot store transparency. When you convert a transparent PNG or WebP to JPG, those see-through areas have to become something — so they're filled with a solid colour (white by default, but you can choose).

If you need to keep transparency — a logo to drop onto different backgrounds, say — convert to PNG or WebP, not JPG. Our converter lets you pick the fill colour when you do choose JPG, so at least the result is predictable.

Quality settings, briefly

For JPG and WebP you'll see a quality control. A few pointers:

• 80–90% is the sweet spot for most photos: visually indistinguishable from the original at a fraction of the size.
• Below ~60% you'll start seeing blocky artefacts, especially around sharp edges and text.
• PNG has no quality slider because it's lossless — you either keep it as PNG (larger, perfect) or convert to a lossy format to save space.

File size, at a glance

Format choice is really a conversation about file size, and the differences are dramatic. Take a typical photograph: as a PNG it might weigh several megabytes, because PNG stores every pixel losslessly. Save that same photo as a high-quality JPG and it can shrink to a fraction of the size with no visible difference. Convert it to WebP and it often shrinks again. That's why screenshots — which many systems save as PNG by default — are such common candidates for conversion: a screenshot of a mostly-photographic screen can be an order of magnitude smaller as a JPG. The reverse is also true, though: converting a graphic with large flat areas of colour or sharp text to JPG can actually make it look worse and sometimes barely smaller, because JPG's compression is tuned for photos, not hard edges. So the file-size win depends on the content, not just the format. When you convert, glance at the before-and-after size the tool reports — if a "space-saving" conversion didn't actually save much, the original format was probably the right one.

Related tools

• Image Compressor — squeeze the file smaller after converting.
• Image Resizer — change pixel dimensions.
• Background Remover — create the transparency that PNG and WebP preserve.
• Image Color Picker — grab exact colours from an image.

Common questions

Which conversions are supported? Any direction between JPG, PNG, and WebP — PNG to JPG, JPG to WebP, WebP to PNG, and so on.

What happens to transparency when I convert to JPG? It's filled with a background colour you choose, because JPG doesn't support transparency. PNG and WebP keep it intact.

Which format is best for the web? WebP, in most cases — smaller files than JPG at the same quality, with transparency support. Use JPG for maximum compatibility and PNG when you specifically need lossless graphics.

Is anything uploaded? No. Conversion runs in your browser, so your images never leave your device.

Will converting a JPG to PNG improve its quality? No — quality lost in the original JPG can't be recovered. PNG will just store the existing (already-compressed) image losslessly, in a larger file.

The bottom line

Pick the format for the job: JPG for photos, PNG for graphics and transparency, WebP when you want the best of both on the web. Then convert freely and privately with our Image Converter — no upload, no watermark, no sign-up.

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Prime Webkit builds free tools like this, and develops web and mobile apps where getting image formats right is the difference between fast and frustrating. If you're building something that handles media, our app team can help.