How to Convert an Image Without Losing Quality (or Leaking It)

Changing a file from .png to .jpg sounds like renaming it. It isn't. The picture is decoded and written again from scratch, and three things can quietly change on the way through: how sharp it looks, whether it still has a transparent background, and what the file knows about you.

If you only need the job done: open the Image Converter, drop your files in, choose JPG, PNG or WebP, and download. It runs in your browser, so the pictures stay on your machine. If you want to understand what you're trading away — and when you're trading away nothing at all — read on.

What actually happens when you convert

An image file has two parts: the pixels, and the instructions for how those pixels were squeezed into bytes. Converting leaves the pixels alone in principle and replaces the squeezing. The file is decoded back to a plain grid of coloured dots, then re-encoded using the rules of the new format.

That decode-and-re-encode step is where everything interesting happens, and it explains the single most common surprise: renaming a file does not convert it. Changing photo.webp to photo.jpg in Finder or File Explorer leaves WebP data inside a file wearing a JPG name. Some apps are forgiving and sniff the real contents; upload forms and older software usually just reject it. A real conversion rewrites the bytes.

It also explains why conversion is not a size tool. Going from PNG to JPG often shrinks a photo dramatically, but that's a side effect of JPG being a better fit for photographs — not of conversion itself. If your actual goal is a smaller file, that's a different job with different levers, covered in how to compress an image without ruining it.

When conversion costs you nothing, and when it costs you a little

Formats fall into two camps. Lossless formats — PNG is the common one — reproduce every pixel exactly. Lossy formats — JPG, and WebP in its usual mode — throw away detail the eye is unlikely to miss in exchange for much smaller files.

That gives you four cases, and only one of them is genuinely risky:

Note the trap in the first row. People sometimes convert a JPG to PNG hoping to "restore" quality. It cannot work — the detail JPG discarded is gone, and PNG simply records the damaged result losslessly, in a much larger file. PNG preserves; it doesn't repair.

Generation loss, and how to avoid it

Every time a photo passes through a lossy encoder it loses a little more. Convert a JPG to WebP, then back to JPG, then re-save it from an editor, and you've stacked three rounds of approximation. Each pass is subtle; the pile-up isn't. Edges go mushy, skies develop faint blocks, and dark areas get blotchy.

Three habits avoid nearly all of it:

• Always convert from the best original you have, not from a copy you already converted once. Go back to the camera file or the export from your editor.
• Convert once, to the format you actually need. Don't route through an intermediate format "just in case".
• Use a high quality setting when it matters. The converter's High and Maximum settings leave far more detail than the default middle ground, at the cost of a larger file.

If you're keeping a master copy of something you'll re-edit repeatedly, keep it in a lossless format and export lossy copies for sharing. The master never degrades.

Transparency: the decision JPG makes for you

PNG and WebP can store transparency. JPG cannot — there is no mechanism in the format for a see-through pixel. So when you convert a transparent logo to JPG, something has to fill the gap, and the encoder picks a colour whether you asked it to or not. Usually white. Sometimes black, which is how people end up with a logo sitting in a mourning rectangle.

This is worth controlling rather than discovering. The converter asks for a background colour whenever JPG is the output and lets you set it to white, black or any custom colour — so you can match the background it will actually sit on. If the image needs to stay see-through, the answer is simply not to use JPG: keep it as PNG, or use WebP.

Converting for a destination

Most conversions aren't driven by taste. Something downstream refused the file. It helps to pick the format by asking where the image is going.

Two destinations deserve their own note. WebP is a web format, not a sharing format. Browser support is no longer the issue; the issue is everything that isn't a browser. Plenty of desktop apps, email clients and upload fields still won't take a .webp, which is exactly why people arrive at a converter needing to go the other way. And iPhone photos are their own case: they arrive as .heic, which a lot of non-Apple software can't open at all. The converter reads HEIC as an input, and there's a dedicated HEIC to JPG tool plus a fuller walkthrough in converting HEIC without uploading your photos.

If you're still deciding which format you want rather than how to get there, the companion piece — JPG, PNG and WebP explained — compares them properly.

Converting a whole folder at once

One-at-a-time conversion is fine for one file and miserable for ninety. Batch conversion matters more than it sounds, because the alternative — repeating a web upload ninety times — is where both your afternoon and your privacy go.

Add the whole set at once and each image is converted with the same output format and quality settings. A single file downloads on its own; several come back together in a ZIP. A few practical notes from the way this works in practice:

• Mixed inputs are fine. A folder of JPGs, PNGs and HEICs can all go to WebP in one pass.
• Filenames are preserved, with only the extension changed, so invoice-03.png becomes invoice-03.jpg and your ordering survives.
• Dimensions are untouched. Every image keeps its exact pixel size and orientation — portraits don't come back sideways.
• Very large batches are limited by your own device, not a server quota. Hundreds of phone photos will work but will warm your laptop up; if the tab struggles, do it in two passes.

The side effect nobody mentions: metadata

Photos carry more than pixels. A camera or phone writes EXIF metadata into the file: the exact time, the camera and lens, the settings, and — if location services were on — the GPS coordinates of where you were standing. That data is a real privacy consideration, and conversion interacts with it in a way that catches people out in both directions.

Because an in-browser converter decodes the image to raw pixels and writes a brand-new file, the EXIF block in the original is not carried across. The output is a clean re-encode of the picture itself. That's usually a quiet win: convert a holiday photo and the GPS tag doesn't come with it.

But treat that as a side effect, not a guarantee, and don't lean on it:

• It only applies to the file you just converted. The original still has every tag, sitting in your folder.
• Other tools behave differently. Many converters — particularly server-side ones — deliberately preserve EXIF.
• Metadata isn't the only thing in a picture that identifies you. A visible street sign, a name badge or a reflection survives any conversion perfectly.

If stripping identifying data is the actual goal rather than a bonus, do it deliberately with the Metadata Remover, and read what EXIF and GPS data reveal about your photos. For visible details in the frame, that's redaction, not conversion — see how to redact an image properly.

What a browser-based converter can't do

Honesty about limits is more useful than a feature list, so here is where this tool stops:

• It converts between JPG, PNG and WebP, and reads HEIC. It does not output AVIF or JPEG XL. AVIF is well supported in current browsers but patchy in email clients and older devices; JPEG XL, as of late 2026, is on by default in Safari and still behind a flag in Chrome and Firefox. Neither is a safe default for files you send to other people.
• It doesn't read GIF, TIFF, BMP or SVG, and vector formats like SVG aren't really a conversion target anyway — flattening a vector to pixels throws away the thing that made it a vector.
• It doesn't resize. Output dimensions always match the input. If you need fewer pixels, that's the compressor, which can cap the longest side.
• It can't undo a previous lossy save. Nothing can.

Why the upload matters for something this trivial

Search for an image converter and most of the first page will convert by sending your file to a server. For a stock graphic, fine. But think about what people actually convert: a photo of a passport for a visa application, a screenshot of a bank statement, a child's school photo, a snapshot of a signed contract. Handing all of that to an unknown company — along with the GPS coordinates in the metadata — to perform an operation your own device can do in half a second is a poor trade, and the privacy policy you didn't read is the only thing governing what happens next.

The RedactLocal converter does the work in the page. Your file is read by the browser, decoded on your machine, re-encoded on your machine, and handed back to you as a download. Nothing is transmitted. The practical proof is simple: load the page, turn off your Wi-Fi, and convert anyway — it still works, because there was never a server in the loop.

Frequently asked questions

Does converting an image lose quality?

It depends which direction. Converting to PNG is lossless — no new quality is lost. Converting to JPG or WebP re-compresses the picture, so there is one round of loss, which is invisible at a high quality setting for photographs but visible on sharp text and flat colour. Converting a lossy file to another lossy format stacks a second round on top of the first; that's the case worth avoiding.

Why did my transparent image get a white background?

You converted it to JPG, which has no way to store transparency, so the see-through areas were filled with a solid colour. Keep the file as PNG or WebP to preserve transparency, or choose the fill colour deliberately when converting to JPG.

Can I convert a JPG back to its original quality?

No. Lossy compression discards detail permanently. Converting a JPG to PNG preserves exactly what's left, in a larger file, but it cannot recover what the first save threw away.

Does converting an image remove EXIF and GPS data?

With this converter, yes, as a side effect — the output is written fresh from the decoded pixels, so the original metadata block isn't carried over. Don't rely on that as a privacy measure in general, though: other converters preserve metadata on purpose, and your original file still has all of it. If removing it is the goal, use the Metadata Remover.

Can I just rename the file extension instead?

No. Renaming changes the label, not the contents. The file still holds data in the old format, which is why upload forms reject it. A real conversion re-encodes the image.

Can I convert hundreds of images at once?

Yes. Add the whole batch and they're converted with the same settings; one file downloads directly and several arrive in a ZIP. Because the work happens on your own device, the practical ceiling is your computer's memory rather than an upload limit — split very large batches if the tab slows down.

Why is my converted file bigger than the original?

You probably converted a photograph to PNG. PNG is lossless, which for a continuous-tone photo means storing far more data than JPG needed. For photos, convert to JPG or WebP; keep PNG for graphics.

Does it work on Windows, Android or a Chromebook?

Yes. It runs in the browser, so any current browser on any operating system works, with no app or plugin to install.