Image Converter
Convert between JPG, PNG, WebP and AVIF, with an honest answer about what your browser can actually write.
85 is the usual sweet spot for photographs.
JPEG cannot store transparency, so it has to become a colour.
Drop an image here
or paste a screenshot with Ctrl+V. Nothing is uploaded.
Everything here runs on your device. Nothing you enter is uploaded or stored.
Convert an image between JPG, PNG, WebP and AVIF without uploading it. The conversion itself is the easy part — the useful part is being told the truth about what your browser can do and what the conversion will cost you.
How to use it
- Drop an image onto the panel, press Choose images, or paste from your clipboard.
- Pick the format you want. Options your browser cannot encode are disabled, with the reason shown.
- For lossy formats, set the quality. For JPEG output, choose the colour that replaces any transparency.
- Read the estimated size change, then press Download. Add several files first and the batch button returns a ZIP.
The lie most converters tell
Here is a genuine problem with the browser API these tools are built on. When you ask a canvas to produce an AVIF file, the call does not fail on a browser without an AVIF encoder. It silently returns a PNG instead.
The consequence is that a converter which trusts the format it asked for will hand you photo.avif that is really a PNG, three times larger than the JPEG you started with, and tell you the conversion succeeded. You would only discover it when something refused to open the file.
The only reliable check is to encode a tiny test image in each format and inspect the type of the data that came back. That is what happens when this page loads, before you choose anything. Formats that fail the test are disabled and labelled, and the panel states plainly which of the four your browser can write. Disabling an option with a reason attached is more honest than hiding it and leaving you wondering why AVIF is missing.
What each conversion actually costs
Lossless to lossy — PNG to JPEG or WebP — discards detail permanently in exchange for a much smaller file. This is usually the right trade for photographs, and it is the single biggest saving available, because a photograph stored as PNG is often five to ten times larger than it needs to be.
Lossy to lossless — JPEG to PNG — cannot undo the first compression. You keep every artefact the JPEG already has and then store them inefficiently. The file gets bigger, not smaller. Do it only when you need transparency or lossless editing from that point on.
Lossy to lossy — JPEG to WebP — re-encodes pixels that were already compressed once, so the first encode’s artefacts get baked in and compressed again. It is still usually worth it for the size saving, but it is not a free conversion, and any tool describing it as lossless is wrong.
The tool states which of these three cases you are in every time you change the target format.
What it does not do
It converts one image at a time into one format, and it does not read RAW camera files, HEIC, SVG or PDF, because browsers cannot decode those on a canvas. Animated GIFs and animated WebP lose their animation and come out as a single frame. Metadata is not carried across, which is usually what you want — if you need to inspect or deliberately strip it, the EXIF viewer does that properly.
Nothing leaves your device. There is no upload, no queue, and no daily limit.
Format comparison
| Format | Lossy | Transparency | Typical size vs JPEG | Use it for |
|---|---|---|---|---|
| JPEG | Yes | No | Baseline | Photographs that must open anywhere |
| PNG | No | Yes | 3–10x larger | Screenshots, logos, line art |
| WebP | Either | Yes | 25–35% smaller | The sensible default for the web |
| AVIF | Either | Yes | 40–50% smaller | Size over compatibility |
Questions
Why is my converted PNG bigger than the JPEG I started with?
Because PNG is lossless and JPEG is not. Converting JPEG to PNG cannot recover the detail JPEG already discarded — it just stores the damaged pixels without compressing them further, which usually makes the file two to five times larger. Converting to PNG only helps if you need transparency or plan to edit the image repeatedly.
Which format should I actually use?
For photographs on the web, WebP is the sensible default — it is typically 25 to 35 per cent smaller than JPEG at the same visible quality and every current browser reads it. Use JPEG when something old or unusual has to open the file. Use PNG for screenshots, logos and anything needing transparency. Use AVIF when size matters more than compatibility.
What happens to transparency when I convert to JPEG?
JPEG has no alpha channel, so transparency cannot survive. Tools that ignore this composite the image against black, which is why PNG-to-JPEG conversions so often come back with a black background. This tool fills transparent areas with a colour you choose, defaulting to white, and warns you before the download rather than after.
Why is AVIF disabled in my browser?
Because that browser has no AVIF encoder. This matters more than it sounds — asking a browser for a format it cannot write does not fail, it quietly hands back a PNG with the wrong file extension. Rather than let that happen, the tool encodes a tiny test image, checks what type actually came back, and disables the formats that failed.
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