What “transparent” means in a PSD
A PSD stores transparency per pixel, as an alpha value from 0 (fully clear) to 255 (fully opaque). PNG stores exactly the same thing, which is why PNG is the usual export for logos, product cut-outs, stickers, UI icons and overlays. JPG cannot store it.
When Photoshop saves with Maximize Compatibility (the default), the file also carries a flattened copy of the visible document, alpha included. Layerzip uses that copy for the flattened PNG, so what you get matches what the document looked like in Photoshop at save time: hard edges stay hard, feathered edges stay soft, shadows stay partly see-through.
Common reasons a PNG comes out opaque
- A visible Background layer. Photoshop’s locked Background layer is always opaque. If it was showing, the stored composite is opaque.
- A full-size fill or adjustment layer set to a solid colour.
- You picked JPG. JPG flattens transparency onto white.
If you cannot re-save the PSD, export each layer instead: Export all layers as PNG writes one PNG per layer, each with its own alpha, so you can drop the background layer and keep the rest.
Limits
- Free: one flattened PNG at a time, files up to 30 MB and 8,000 px on the long edge. Paid plans raise this to 200 MB and 12,000 px (Pricing).
- 16-bit and 32-bit documents are read, but the PNG is 8 bits per channel.
- CMYK documents are converted to RGB with an approximate profile, so colours can shift slightly. Transparency is not affected.
- Files saved without a composite get a best-effort flatten that uses normal blending only.