PNG encoding is lossless; the full HEIC conversion is not
Privacy mode decodes the primary HEIC image in the browser and encodes the decoded pixels as PNG without uploading the image. Cloud mode uploads the image for server-side conversion and deletes the uploaded image by default one day later. PNG does not add JPEG-style lossy compression to the decoded pixels, but neither mode can recreate every original HEIC feature.
HEIC to PNG high quality means protecting the decoded pixels
PNG is useful when you want to avoid adding another JPEG-style lossy encoding step after HEIC decoding.
In Privacy mode, the browser encoder stores the decoded 8-bit RGBA pixel result with PNG's lossless compression. Cloud mode performs the conversion through the server-side pipeline. In either mode, PNG protects the decoded pixel data it receives, but the resulting file may be substantially larger than a JPG.
What the PNG output should not be assumed to preserve
The output is an image conversion, not a bit-for-bit copy of the HEIC container.
- 10-bit precision or HDR behavior from the original source
- ICC information, gain maps, or other color-related container data
- Depth data, auxiliary images, sequences, or non-primary frames
- Every original HEIC metadata field
Both modes retain metadata supported by PNG by default and do not intentionally strip it. Check the PNG result if metadata is important, because HEIC-specific fields and container features may not have a PNG equivalent.
HEIC to PNG quality FAQ
Answers about PNG compression, decoded pixels, metadata, and HEIC source features.
PNG encoding is lossless for the decoded pixels supplied to the encoder. In Privacy mode, the browser pipeline first decodes the HEIC primary image to 8-bit RGBA; Cloud mode uses the server-side conversion pipeline. Neither mode makes the complete HEIC source a lossless, bit-for-bit PNG copy.
Yes. PNG uses compression, but that compression is lossless for the decoded pixel data written to PNG. The resulting file can still be larger than a JPG.
No. Both modes retain metadata supported by PNG by default and do not intentionally strip it, but the complete HEIC container, 10-bit or HDR data, gain maps, depth data, auxiliary images, sequences, and HEIC-specific metadata may not map to PNG.
Privacy mode processes image data directly in your browser and does not upload the images. Cloud mode uploads images for server-side processing; uploaded images are deleted by default one day later. The output-quality boundary still depends on what PNG can represent.