Batch Image Format Converter

Convert multiple images between PNG, JPG, WebP, BMP, and AVIF formats at once.

Tested tool guide Tested browser tools Checked August 16, 2026

What Batch Image Format Converter does and how it behaves

Batch Image Format Converter takes several image files in one selection and creates converted copies in PNG, JPG, WebP, BMP, or AVIF, avoiding a separate conversion for every file. Processing stays in the browser, which matters when source images should not be uploaded. The common surprise is that changing formats does not improve source quality. Converting a small or already compressed JPG to PNG cannot restore detail discarded by JPEG compression, and the resulting PNG may be larger.

How the result is produced

Batch input and output

Add multiple images in any of the listed source formats and select the required destination format. The batch applies that format choice to the selected files in one run. This is an image re-encoding operation, not merely a filename-extension change. A format-only conversion does not imply resizing, so confirm the resulting pixel dimensions if exact dimensions are important.

Format characteristics

The destination controls which image features can be represented. PNG provides lossless raster storage and alpha transparency. JPEG is ordinarily lossy and has no alpha channel. WebP and AVIF can represent lossy or lossless images and transparency. BMP has several variants and pixel layouts. These differences affect file size, compatibility, transparency, and whether another lossy encoding step occurs.

Good uses

Convert a set of PNG screenshots to JPG before placing them in a system that accepts only JPEG images.
Create WebP or AVIF copies of several product images for a website while retaining the original files separately.
Turn a mixed collection of JPG, PNG, and BMP images into one consistent format for a downstream application.

Limits and checks

Do not judge the conversion only by the new extension. Open representative outputs and inspect dimensions, orientation, color, transparency, and fine detail.
JPG cannot retain transparent pixels. When converting PNG, WebP, or AVIF images with alpha to JPG, inspect the resulting background because the format requires opaque output.
A smaller file is not automatically a better result. Lossy output may remove visible detail, while lossless PNG output made from an existing JPG may be larger without recovering quality.

Common questions

Does converting a JPG to PNG make the image lossless?

No. The PNG stores pixels obtained by decoding the JPG without adding a lossy PNG compression stage, but JPEG damage already present remains. It cannot recreate discarded texture, sharp edges, or color information. Use the original lossless source when preservation matters, and compare the converted image with that source rather than with the compressed JPG.

Will transparent backgrounds survive every conversion?

No. PNG, WebP, and AVIF can carry alpha transparency, but JPEG cannot. A transparent source converted to JPG must become opaque, so check the output to see how transparent areas were filled. BMP has multiple variants and transparency support is not consistently interpreted by software, making it a poor assumption for interchange without testing.

References and verification

The behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.