What does an image converter do?
An image converter re-encodes a picture from one format to another. The pixels are decoded, drawn onto a canvas at the size you want, and written back out in the target format with a quality setting that applies only to the lossy ones. The result is a new file that looks the same but is stored differently — often much smaller, sometimes a little softer, and occasionally without the transparency the original had.
The choice of format is the interesting decision, because it is really a decision about what the image contains. PNG stores every pixel exactly, which suits screenshots, diagrams, logos and anything with flat colour and hard edges, and costs a great deal for a photograph. JPEG discards detail in a way that survives compression well for photographs and badly for text and line art. WebP does both jobs: it can be lossless or lossy, generally beats JPEG on size at the same quality, and keeps transparency where JPEG cannot.
Batch conversion is the reason a tool is worth having rather than an image editor. A folder of screenshots that need to be WebP, or a set of photographs that needs to be JPEG at a sane quality, is a job of fifty identical operations — which is also where the option to cap the width matters, since resizing does more for the file size than any quality setting can.
How to convert images to another format
- Drop in one image or several. Each is read locally and listed as a thumbnail you can remove.
- Choose the target format. WebP is the best default for the web; JPG for compatibility; PNG when the image has text, flat colour or transparency to keep.
- If the format is lossy, set the quality. Between 80 and 90 is where the size collapses without the difference being visible.
- Optionally set a maximum width. Anything wider is scaled down proportionally, which cuts the file size far more than quality alone.
- Press Convert. The table reports the size before and after for each file, so the effect of the settings is visible rather than assumed.
- Download the single image, or take the whole batch as a ZIP.
Image Converter limits and rules
| Item | Limit |
|---|---|
| Input formats | Whatever the browser can decode: PNG, JPG, WebP, GIF, AVIF, BMP, ICO and SVG |
| Output formats | PNG, JPG and WebP |
| File size | 25 MB each, and as many at a time as you need |
| Quality | 10 to 100, applied only to JPG and WebP |
| Width limit | Optional; keeps the aspect ratio and never enlarges |
| Transparency | Preserved in PNG and WebP; a JPG gets a white background instead |
| Animation | Not preserved — an animated GIF or WebP converts to a single frame |
| Metadata | Not copied: EXIF, ICC profiles and location tags are dropped |
When to use it
- Turning a folder of PNG screenshots into WebP so a page loads faster without visibly changing.
- Converting HEIC or AVIF photographs to JPG for a system that will not accept the newer formats.
- Shrinking a set of photographs before attaching them to an email or uploading them to a form.
- Producing a PNG from a JPG when the image contains text that JPEG artefacts have made fuzzy.
- Changing the format of an image before using it as a favicon, a thumbnail or a profile picture.
Is it private?
The images are decoded and re-encoded in your browser using the canvas API, and they are never uploaded. Nothing is stored and there is no queue behind the page. Closing the tab discards the files, which is why the downloads have to happen in the same session.
Frequently asked questions
WebP if you are publishing to the web and want the smallest file for a given visual quality, with transparency supported. JPG if something downstream needs a format that has been universal for thirty years — a print shop, an old form, an upload that rejects anything else. PNG when the image has text, sharp edges or transparency, or when it will be edited again, since it is the only one of the three that stores every pixel exactly.
Between 80 and 90 for photographs, and it is rarely worth going above 90 — the file grows quickly and the difference is not visible. Below about 60 the blocking artefacts start to show in smooth gradients such as sky, and below 40 they are obvious. For a graphic with text or a logo, the answer is different: use PNG instead of pushing JPEG quality up, because JPEG's artefacts around hard edges are exactly what makes small text look muddy.
Because PNG is lossless and does not throw anything away. Converting a photograph from JPEG to PNG is a step backwards on size: the JPEG was already compressed, and PNG faithfully stores every pixel of the artefacts it introduced, usually at three to ten times the size. The formats are not interchangeable ranks of quality — they are different trades. Convert to PNG when something needs exact pixels, not when something needs to be smaller.
It is replaced by a solid colour, because JPEG has no way to represent a transparent pixel. This tool fills those pixels with white rather than leaving the choice to the encoder, which would otherwise render transparent areas as black in most browsers. If transparency matters, choose PNG or WebP; if it does not and you want the smallest file, JPG with a known background colour is the right answer.
Only when the target is lossy, and then it does so permanently. A JPEG encoded at 85 is not the original — it is an approximation the eye mostly accepts — and re-encoding that file at 85 again compounds the loss, because the second encoder sees the first one's artefacts as image detail and preserves some of them. Converting from a lossless source to a lossy format once is normal practice; converting between two lossy formats repeatedly is what gradually ruins an image.
No. The canvas API gives back pixels and nothing else, so the file you download carries no EXIF block, no camera model, no capture date and no GPS coordinates — the tag written by the encoder is all there is. That is usually a benefit when posting a photograph publicly, and it is occasionally a surprise when the orientation tag disappears at the same time. Images that need their metadata kept should be converted with a tool that copies it explicitly.
Related tools
Written and maintained by Md. Nur Hossain Repon.