Batch image conversion comes up whenever you need to prepare a set of images for the web: converting a folder of PNG screenshots to WebP, converting a set of JPEGs to AVIF for better compression, or standardising a mixed set of formats into a single format for consistency. Doing it one file at a time is unnecessary.
Why format consistency matters for websites
A mix of JPEG, PNG, and GIF images on a page loads inconsistently — browsers optimise delivery differently for each format, and the total page weight is higher than it needs to be. Converting all images to WebP reduces total page weight by 20–40% and allows a consistent Content-Type header, which simplifies caching and CDN configuration.
How to batch convert images in your browser
- 1Go to tools.zenwebx.com/image-converter.
- 2Drop up to 10 images (JPG, PNG, WebP, AVIF, BMP, or GIF — up to 20 MB each).
- 3Select your output format: WebP is recommended for web use.
- 4Click Convert. All files are processed simultaneously.
- 5Download individual files or grab them all as a ZIP.
Processing runs in your browser using the HTML5 Canvas API. Nothing is uploaded. The ZIP download lets you grab all converted files in one click.
Format conversion quality notes
- PNG → WebP (lossless): perfect quality, 26% smaller than PNG on average.
- JPEG → WebP (lossy): similar quality to the original JPEG, 25–34% smaller.
- JPEG → PNG: the JPEG quality is baked in — converting to PNG makes it lossless from this point forward but doesn't recover quality already lost.
- Any format → AVIF: best compression but slightly slower to process in-browser.
The batch limit is 10 files per conversion. For larger batches, run multiple conversions. Each batch is processed completely independently — there's no quota or session limit.
Batch convert your images
Up to 10 files at once. Download all as a ZIP. No upload, runs in your browser.
Open Image Converter