Are my images uploaded to a server?

No. All conversion happens entirely inside your browser using the HTML5 Canvas API. Your images are never sent to any server and never leave your device.

Does converting hurt image quality?

Converting between lossless formats (e.g. PNG → PNG, PNG → BMP) is lossless - no quality is lost. Converting to a lossy format (JPEG, WebP, AVIF) introduces some compression. Use a quality of 90–100 to minimise quality loss, or use PNG output for perfect fidelity.

Can I convert HEIC to JPEG online?

HEIC (the format used by iPhones) is not natively decodable by most browsers, so this tool cannot convert HEIC files directly. On a Mac you can use Preview to export a HEIC as JPEG, or use the Files app on iPhone to share as JPEG.

Why does my PNG become larger after converting to JPEG?

PNG uses lossless compression, which is very efficient for images with flat colors, text, or transparency. JPEG is optimised for photographs and continuous-tone images. If your PNG is a logo or screenshot, JPEG may produce a larger file. Try WebP instead - it handles both photo and graphic content efficiently.

What formats support transparency (alpha channel)?

PNG, WebP, and AVIF all support transparency. JPEG and BMP do not. When converting a transparent image (PNG, WebP) to JPEG or BMP, the transparent areas are filled with the background color you select (default: white).

What is WebP and why should I use it?

WebP is a modern image format developed by Google that delivers superior compression for both photographs and graphics. WebP lossy images are typically 25–34% smaller than comparable JPEGs. WebP is supported by all major browsers since 2020 and is the recommended format for web images.

AVIF (AV1 Image File Format) is the newest major image format, based on the AV1 video codec. It delivers even better compression than WebP - often 50% smaller than JPEG at the same quality. AVIF is supported in Chrome 85+, Firefox 113+, and Safari 16+. This tool feature-detects AVIF support and warns you if your browser cannot encode to AVIF.

Can I convert animated GIFs?

The Canvas API only reads the first frame of an animated GIF. The animation is not preserved in the output. For animated image conversion you would need a specialised tool.

Image Format Converter

HEIC / HEIF (Apple format)

HEIC (High Efficiency Image Container) is Apple's default photo format since iOS 11 / macOS High Sierra. It uses the HEVC codec and achieves roughly 50% better compression than JPEG at equivalent quality. Despite this, many web services, older Windows applications, and Android devices don't natively support HEIC. Converting to JPEG or WebP is the most reliable way to share HEIC photos broadly. Note: browser-based HEIC conversion may not be supported in all browsers due to codec licensing.

Color profile preservation

Images can contain embedded ICC color profiles (e.g., sRGB, Display P3, Adobe RGB) that tell displays how to interpret the color values. When converting between formats, the HTML Canvas API works in the sRGB color space and does not preserve embedded ICC profiles. This is acceptable for most web images but can cause visible color shifts for wide-gamut photography (Display P3, Adobe RGB) or print workflows where color accuracy is critical. For print-critical work, use dedicated software like Photoshop or ImageMagick to preserve ICC profiles during conversion.

PNG vs JPEG: when to use each

Choosing the right image format is as important as choosing the right quality setting. The two most common formats: JPEG and PNG: serve different purposes:

JPEG is a lossy format optimised for photographs and images with smooth color gradients. It achieves excellent compression because it discards subtle color detail that the eye can barely perceive. It does not support transparency.
PNG is a lossless format that retains every pixel exactly. It is the best choice for screenshots, logos, UI icons, and images that contain text or sharp edges. PNG supports full transparency (alpha channel). The tradeoff is that PNG files are typically much larger than JPEG for photographs.

A common workflow: use PNG during design/editing (to avoid generational quality loss when re-saving), then export to JPEG or WebP for final web delivery.

What is WebP?

WebP is a modern image format developed by Google in 2010. It supports both lossy and lossless compression, as well as transparency and animation. Key advantages:

25–34% smaller than JPEG at equivalent visual quality (lossy mode)
26% smaller than PNG in lossless mode
Full alpha transparency support
Supported in all major browsers since 2020 (Chrome, Firefox, Safari, Edge)

If you are serving images on the web, converting your JPEG and PNG images to WebP is one of the easiest ways to reduce page load time without changing image quality.

What is AVIF?

AVIF (AV1 Image File Format) is based on the AV1 video codec, developed by the Alliance for Open Media. It is the most space-efficient widely-supported image format available today:

~50% smaller than JPEG at the same visual quality
Supports HDR, wide color gamut, and transparency
Browser support: Chrome 85+, Firefox 113+, Safari 16+

AVIF encoding can be CPU-intensive, so encoding time is longer than JPEG or WebP. For most websites targeting modern browsers, WebP is a practical choice today; AVIF is the future. This tool detects whether your browser supports AVIF encoding and warns you if it does not.

Transparency and background color

PNG, WebP, and AVIF can store pixels with an alpha (transparency) channel. JPEG and BMP cannot. When you convert a transparent image to JPEG or BMP, the transparent areas must be filled with a solid color: this tool defaults to white but you can choose any color via the background color picker.

Tip: if your image has a transparent background and you are converting to JPEG for a web page with a specific background color, set the background color to match the page background so the image blends seamlessly.