PNG, JPG & WebP Converter
Convert between PNG, JPG, and WebP in your browser. Use PNG for sharp text, JPG for photos, WebP for smaller web files.
Images never leave your browser - processed 100% locally.
Preview updates instantly when you change format
Runs in your browser. Nothing you enter is uploaded.
Overview
A file extension is a container decision, and containers are not interchangeable. PNG stores every pixel exactly and carries transparency. JPEG throws away detail your eye is unlikely to miss and has no concept of a transparent pixel. WebP does either job, usually in a smaller file, and is a slightly newer arrival that a small amount of older software still refuses.
This converter re-encodes an image into whichever of those three you pick. The pixel dimensions are preserved exactly; what changes is how those pixels are stored, and - for the lossy formats - how much of the original information survives the round trip.
The one conversion that changes your image visibly rather than invisibly is anything transparent going to JPEG, and that case is worth understanding before you click download.
What happens to transparency when you choose JPEG
JPEG has no alpha channel. There is no representation of a see-through pixel in the format, so a converter has to decide what to put there instead, and this one fills the canvas with white before drawing your image onto it. A logo with a transparent background becomes a logo on a white rectangle - which is fine on a white page and obviously wrong on a dark one.
The effect is most damaging on soft edges. Anti-aliased text and rounded corners are stored as partially transparent pixels, and compositing them onto white produces a pale halo that becomes glaringly visible the moment the image sits on a coloured background. A logo that looked clean as a PNG acquires a white fringe as a JPEG, and no amount of quality adjustment removes it because the information is gone.
The rule that follows is simple and worth being rigid about: anything with transparency stays PNG or WebP. JPEG is for photographs, which have no transparency to lose and benefit most from lossy compression. If you need a JPEG of a transparent graphic, composite it deliberately onto the correct background colour in an editor first, rather than letting a converter choose white for you.
- JPEG conversion fills transparent areas with white, permanently.
- Soft anti-aliased edges pick up a visible pale halo in the process.
- Photographs are the right subject for JPEG; graphics and logos are not.
- To flatten intentionally, choose the background colour yourself before converting.
Choosing between the three formats for a given image
Work from what the image contains. Photographs - continuous tone, no flat areas, no hard edges - compress dramatically well in JPEG or WebP and pointlessly badly in PNG, where a phone photo can easily be five times larger than necessary. Screenshots, diagrams, and anything with text or flat colour are the reverse: PNG keeps edges crisp, while lossy compression stipples the boundaries between flat regions.
WebP is the modern default for both cases when the destination is a web page. It compresses photographs smaller than JPEG at comparable visible quality and supports transparency like PNG, which makes it the only one of the three that does not force a trade. Its limitation is compatibility with things other than browsers: some design software, some older operating system previewers, and a number of upload forms still reject it.
That compatibility question, not the compression question, is usually what decides the answer. For a website, WebP. For an email attachment, a print supplier, or an upload field with an unclear allowlist, JPEG for photographs and PNG for graphics remain the choices nothing will refuse.
The decode, redraw, and re-encode path
Your file is read into the page and decoded into an image, and a canvas is created at exactly its natural width and height - so no resampling occurs and dimensions are identical in and out. If the target is JPEG, the canvas is filled white first; otherwise it is left transparent. Your image is then drawn onto it at the origin, and the canvas is asked to produce a blob in the target format.
Encoding quality is fixed at 0.92 for JPEG and WebP, which is a deliberately conservative setting on the high side of the visually-lossless range for most photographic content. PNG is asked for without a quality argument because it is lossless and the parameter has no meaning there. There is no slider, which is the main functional difference between this tool and a dedicated compressor.
The result is measured, turned into a preview, and held ready for download under your original filename with the new extension. Because the whole path runs through the browser’s own canvas encoder, WebP support depends on the browser rather than on the tool - if the encoder returns nothing, you get an error rather than a silently wrong file. Nothing is uploaded at any stage.
A screenshot with a transparent corner through all three formats
Input
Source: a 1,600×900 PNG export of a UI mockup with flat colour panels, small anti-aliased body text, and a rounded transparent corner. Original file size 412 KB.
Output
PNG → 1600×900, 412 KB, corner still transparent, text edges crisp. WebP → 1600×900, roughly 90 KB, corner still transparent, text edges essentially unchanged. JPEG → 1600×900, roughly 150 KB, corner now white, faint speckling visible along the panel boundaries and around the smallest text.
WebP is unambiguously the right answer here: it is the smallest file and the only lossy option that keeps the transparency. The JPEG is both larger than the WebP and visibly degraded on exactly the content type JPEG handles worst - hard edges between flat colours. Had the source been a photograph rather than a mockup, the JPEG would have been competitive and the PNG would have been the outlier at several times the size.
Limitations
- Encoding quality is fixed at 0.92 for JPEG and WebP with no adjustment, so this is a format changer rather than a size optimiser.
- Transparent pixels are flattened to white when converting to JPEG, and the original alpha cannot be recovered from the result.
- Converting from a lossy source re-encodes it. Going JPEG to JPEG, or JPEG to WebP, adds a second generation of loss on top of the first.
- Dimensions are always preserved, so there is no resizing, cropping, or downscaling available here.
- WebP encoding relies on the browser’s canvas support. Where it is unavailable the conversion fails rather than falling back.
- AVIF, GIF, TIFF, HEIC output and animated formats are not supported - animation is lost if the source has any.
When not to use this tool
- If the goal is a smaller file rather than a different format, the image compressor exposes a quality slider and shows the size trade directly.
- If the image also needs different dimensions, resize first and convert second so the encoder works on the final pixel count.
How to use it
- 1
Decide from the content: photograph means JPEG or WebP, graphic or screenshot means PNG or WebP.
- 2
Check whether the image has transparency before selecting JPEG, since that choice fills it with white irreversibly.
- 3
Pick the format and compare the reported file size against the original before downloading.
- 4
Keep the original file as your master, since re-encoding a lossy output again compounds the loss.
Questions
Which format should I upload to social platforms?
It rarely matters, because every major platform re-encodes what you upload to its own specification anyway. Upload the highest-quality version the form accepts - usually PNG for graphics and a high-quality JPEG for photographs - and let the platform do its own conversion rather than compressing twice.
Will converting a JPEG to PNG improve its quality?
No. PNG stores exactly what it is given, and what it is given is an already-degraded JPEG. You get a lossless copy of lossy data, in a much larger file. The detail discarded by the original encode is not recoverable by any later conversion.
Why is my WebP sometimes larger than the JPEG?
Usually because the source has transparency, which WebP preserves and JPEG discards along with a chunk of file size. It can also happen at a fixed quality setting on certain images - 0.92 is a high setting, and WebP is not universally smaller at every quality on every kind of content.
Does converting strip metadata like EXIF?
In effect yes. The image is decoded to raw pixels, drawn onto a canvas, and re-encoded, so camera settings, timestamps, and location tags do not survive the round trip. That is a privacy benefit if you were worried about them, and a loss if you needed them.