Image Format Converter Image
Convert between PNG, JPEG, WebP, BMP and ICO, with quality, background and icon sizes you control.
Image Format Converter is a free online tool that convert between PNG, JPEG, WebP, BMP and ICO, with quality, background and icon sizes you control. It runs entirely in your web browser using plain JavaScript, so files are processed on your own device and never uploaded to a server. There is no sign-up, no file size limit imposed by the site, no watermark and no paid tier.
- Price
- Free: no account, no quota, no watermark
- Category
- Image
- Where it runs
- In your browser, on your device
- Files uploaded
- None
- Technology
- plain JavaScript
- Settings
- 6
- Works offline
- Yes, after the first visit
About Image Format Converter
The browser decodes the image you drop in, whatever format it is, and draws it onto a canvas. PNG, JPEG and WebP are then encoded by the browser itself. BMP and ICO have no browser encoder, so this tool writes them byte by byte: a 24-bit BMP flattens transparency onto the background color you pick, a 32-bit BMP keeps the alpha channel, and an ICO packs a PNG for every icon size you list, which is the format Windows has read since Vista. The single-purpose converters on this site (JPG to PNG, Image to WebP and the rest) are quicker when you know exactly what you want; this one covers the formats they do not.
How to use it
- Drop an image on the page: PNG, JPEG, WebP, GIF, BMP, ICO, SVG or AVIF.
- Pick the output format. Set the quality for JPEG and WebP, the background color and depth for BMP, or the sizes for ICO.
- Optionally cap the longest side to shrink the image on the way through.
- Download the converted file. The preview updates as you change settings.
The 6 settings
| Setting | What it does | Default |
|---|---|---|
| Output format | Choose from 5: PNG, JPEG, WebP, BMP, ICO. | PNG |
| Quality | 1 to 100, for JPEG and WebP only. | 90 |
| Background where transparency is lost | A hex color used behind transparent pixels for JPEG and 24-bit BMP. | #ffffff |
| BMP depth | 24-bit (no transparency) or 32-bit (keeps transparency). | 24-bit |
| ICO sizes | Comma-separated pixel sizes from 1 to 256. Each becomes an image inside the icon. | 16, 32, 48, 256 |
| Longest side | 0 keeps the original size; anything else scales the image down to that many pixels on its longer edge. | 0 |
Under the hood
| Runs on | plain JavaScript: the Canvas API decodes and re-encodes PNG, JPEG and WebP; BMP and ICO are written byte by byte |
| Controls | Output format, Quality, Background where transparency is lost, BMP depth, ICO sizes, Longest side |
Questions
Why is the BMP so much bigger than the PNG?
BMP is uncompressed: three or four bytes per pixel, plus a small header. A 1920×1080 image is about 6 MB as a 24-bit BMP no matter how simple it is. That is the point of the format for some tools, and the reason to avoid it everywhere else.
Which BMP depth should I use?
24-bit is the safe choice: every program that reads BMP understands it, and transparent areas are flattened onto the background color. 32-bit keeps transparency in an alpha channel, which modern Windows, image editors and browsers honor but some older software ignores or renders black.
What sizes should an ICO have?
For a Windows application icon, 16, 32, 48 and 256 cover the shell, the taskbar and the large tile views. For a website favicon, 16, 32 and 48 are plenty, and the Favicon Generator on this site produces the whole set of files a site needs.
Can it convert to GIF, TIFF or HEIC?
No. Browsers do not encode those, and a GIF encoder would only ever produce a 256-color still image. The formats it writes are the ones that matter for the web and for Windows.
Does converting lose quality?
PNG, BMP and ICO are lossless, so pixels are copied exactly. JPEG and WebP are lossy at any quality below 100, and converting a JPEG to another JPEG re-encodes it, so keep the original if you can.
Is anything uploaded?
No. The file is decoded, drawn and re-encoded by your browser. There is no server on the other end of this page.
Can I use it full screen, or keep a copy offline?
Yes to both. "Full screen" above the tool fills the whole screen (Esc leaves it). "Save as HTML" writes this one tool to a single self-contained file that opens from your own disk without a connection. For everything at once there is a desktop app for Windows, macOS and Linux with all 312 tools inside it.