Does batch conversion reduce image quality?

Only lossy formats like JPEG and WebP reduce quality based on the quality slider. PNG and BMP are lossless, so no quality is lost. Converting from JPEG to PNG does not restore lost quality.

What happens to transparent images when converting to JPEG?

JPEG does not support transparency. Transparent areas in PNG or WebP images will be filled with white when converting to JPEG. Use PNG or WebP output to preserve transparency.

How much smaller will WebP files be compared to JPEG?

WebP is typically 25-35% smaller than JPEG at equivalent visual quality. Results vary depending on the image content. Photos with fine detail see smaller savings than flat graphics.

Can I convert images to AVIF?

Yes, AVIF output is supported in Chrome, Edge, and Firefox. Safari support was added in macOS Ventura. If you need broad compatibility, WebP is still the safer choice.

Are my images sent to a server for conversion?

No. All conversion happens in your browser using the Canvas API. Your files are never uploaded to any server.

Images Tool Box

Conversion

Batch Format Convert Images Online Free

Convert an entire folder of images to a different format in one step. Choose from JPG, PNG, WebP, AVIF, or BMP output, set the quality for lossy formats, and download all converted files as a ZIP. No software required.