Compression: Lossy vs Lossless
HEIC uses lossy compression (HEVC codec): it discards some image data to achieve smaller file sizes. At high quality settings (85–95) the loss is imperceptible in photographs, but artefacts become visible around sharp edges at low settings. PNG uses lossless compression: every pixel is preserved exactly, which matters for text, line art, and screenshots where sharpness is critical.
Transparency
PNG supports an alpha channel (full 8-bit transparency per pixel). HEIC does not support transparency at all- Transparent areas are filled with a solid colour (usually white or black) when converting to PNG. If your image needs a transparent background- Logos, UI icons, product cut-outs- PNG is the correct choice.
File Size Comparison
For photographic content, an HEIC at quality 85 is typically 40–50% smaller than an equivalent PNG. For simple graphics with flat colours and large uniform areas, PNG compression can be very efficient and may even beat HEIC. The crossover point depends heavily on image complexity.
When Not to Use HEIC
- Screenshots of text or code- HEIC compression blurs sharp character edges.
- Images you will edit and re-save multiple times- Each save cycle degrades quality (generation loss).
- Anything requiring a transparent background.
- Infographics and diagrams with solid fills and thin lines.