Why AVIF images end up needing conversion
AVIF is a modern image format built on the compression of the AV1 video codec. Websites like it because it packs photos and graphics into small files, and every current major browser displays it. Outside the browser, support is less complete: plenty of image editors, presentation and word-processing software, design tools and upload forms still do not accept .avif files.
PNG is the natural target when the image is a graphic rather than a photo, or when it has a transparent background. Logos, icons, illustrations, product cut-outs and screenshots all belong in this group. PNG keeps their alpha channel, stays crisp around text and hard edges, and opens in practically any software.
What happens to the image
Convertisio decodes the AVIF in your browser and writes the resulting pixels into the PNG exactly. PNG is lossless, so no new compression artefacts are added, and the file can be edited and re-saved as often as you like without degrading. It is a faithful copy, not an improvement: any smoothing or banding caused by the AVIF's own compression is reproduced precisely.
Transparency is carried over in full, including semi-transparent shadows and anti-aliased edges. A few other details change:
- Bit depth: browsers work with 8 bits per channel, so AVIF images with a higher bit depth are converted at 8 bits per channel.
- Colour: output is in sRGB, and wide-gamut images may look slightly less saturated.
- Animation: the PNG is a still image, so an animated AVIF is converted from its first frame.
- Metadata: EXIF data is not copied to the PNG.
File size: expect growth, especially for photos
The efficiency that makes AVIF attractive on the web does not survive the move to PNG. For graphics with flat colours and sharp edges the increase is often moderate, because PNG compresses that kind of image well. For photographs it can be dramatic: a PNG of a photo is usually several times larger than even a JPG of the same picture, and the AVIF is usually smaller than the JPG.
If the AVIF is a photo without transparency and you only need it to open somewhere, AVIF to JPG gives a far more compact file. If you do need PNG but the file is too large, Settings → Size can fit the image within a maximum width or height; the aspect ratio is kept and nothing is enlarged.
AVIF compared with PNG
| Feature | AVIF | PNG |
|---|---|---|
| Compression | Lossy or lossless | Lossless only |
| Transparency | Full alpha channel | Full alpha channel |
| Animation | Supported | Only through the APNG variant |
| Typical file size | Very small | Larger, especially for photos |
| Bit depth | Up to 12 bits per channel | 8 bits per channel in this converter's output |
| Support outside browsers | Patchy | Almost universal |
| Best for | Delivering images on the web | Editing, transparent graphics, screenshots |
Practical notes
- Browser support: AVIF is decoded natively, so use a current Chrome, Edge or Firefox, or Safari 16.4 or later.
- Batches: up to 10 images per batch, processed one at a time to keep memory use low, then downloaded individually or as a ZIP.
- Large images: each file can be up to 50 MB. On iPhone and iPad, images above Safari's canvas limit of about 16.7 megapixels are scaled down automatically, with a notice.
- Back to the web: once you have finished editing the PNG, a compact format is better for publishing. PNG to WebP makes a much lighter file that still keeps transparency.