Convert image formats locally

How to use this tool

1. Choose supported static images (including 8-bit SDR HEIC/HEIF), a folder or a ZIP; HEIC converts only the declared primary image.
2. Select an output format. For JPEG, choose quality and the transparent-area background.
3. Convert, inspect the result and download the verified file.

Choose a format for the image

PNG preserves transparency and does not use the quality slider. JPEG is useful for photographs but has no alpha channel; choose the background color before conversion. WebP support depends on the browser encoder.

AVIF input requires a static primary AV1 image without container rotation, mirroring, grids or cropping. BMP input accepts uncompressed 24/32-bit rasters. The browser must decode them; AVIF and BMP output are not offered.

The tool checks the actual encoded MIME and signature. An unavailable encoder produces an error, not a renamed PNG. Re-encoding can remove metadata and change file size or visual quality.

HEIC: primary image and supported color

HEIC/HEIF input supports a static 8-bit SDR HEVC primary image, including bounded grids, container rotation/mirroring and straight alpha. If the file contains several still images, only its declared primary image is converted, not necessarily the first. Sequences, 10-bit/HDR, ICC/wide-gamut profiles and clean-aperture crops are rejected. This is not color-managed archival conversion.

HEIC pixels are decoded locally after selection; the decoder is about 3.2 MB before transport compression. Each image is limited to 15 MB, 16 million output pixels and 8192 pixels per side. A task-local Worker has a 45-second deadline; cancel releases it. Full-resolution PNG previews have a separate 50 MB/image and 100 MB/batch limit. Native PNG/JPEG encoding is checked for cancellation and time after it returns.

Process a folder or ZIP locally

Import up to 50 images, 100 MB of input and 100 million pixels in total. Each image must stay within 15 MB, 16 million pixels and 8192 pixels per side. Folder imports include nested folders; non-image files are skipped. All files stay in this page’s memory.

Apply the same settings and process images one at a time. Failed images are listed separately and do not block other files. Preview individual results or download a ZIP with preserved folder paths and unique output names. Encrypted ZIPs, ZIP64 and nested archives are unsupported. Changing settings clears old results; cancelling keeps already completed results.

Common questions