Batch Image Format Converter
Convert multiple images locally with format, quality, resize and transparency controls.
Convert multiple images without uploading them. Import common browser-readable formats, choose a modern output format, resize while preserving aspect ratio, control quality and manage transparent backgrounds.
About This Tool
Batch Image Format Converter is a local browser-based conversion workspace for preparing multiple images at once. It can import common formats your browser can decode, including JPG, PNG, WebP, AVIF, BMP and GIF, then re-encode still images through Canvas. Output options include WebP, JPG, PNG and browser-dependent AVIF or BMP. The tool also includes proportional resize modes, quality control, transparency background handling, per-file status and individual or batch downloads.
How to Use
- Drop one or more supported images into the upload area.
- Choose the output format and optional resize mode.
- Set quality for lossy formats and choose how transparent pixels should be handled.
- Click Convert All and review the result size for each file.
- Download files individually or use Download All for all successfully converted images.
Example
Add several PNG and JPG files, choose WebP at 88% quality, select Fit within max size with 1920 × 1080, then convert the entire batch while preserving each image's aspect ratio.
Frequently Asked Questions
Are images uploaded to a server?
No. Decoding, resizing and conversion happen locally in your browser.
Which input formats can I use?
The picker accepts JPG, PNG, WebP, AVIF, BMP and GIF. A format must also be decodable by the browser you are using.
Which output formats are available?
WebP, JPG and PNG are offered, plus AVIF and BMP when the current browser can actually encode them through Canvas.
Why can AVIF or BMP fail?
Canvas encoding support varies by browser. The tool verifies the returned MIME type instead of silently giving you a PNG with the wrong extension.
What happens to animated GIF files?
Canvas conversion creates a still image from the decoded frame; it does not preserve GIF animation.
How is transparency handled?
PNG and WebP can retain transparent pixels. JPG and BMP are flattened to a background because those outputs are treated as non-transparent in this converter.