What changes in the file
- Layers collapse
- The document becomes a single raster image. Every layer, group, mask, adjustment layer and blend mode is baked into the result exactly as it appeared when the file was last saved in Photoshop.
- Visibility is frozen
- What you get is the composite, so hidden layers stay hidden and visible ones stay visible. There is no way to toggle a layer after conversion, which means the PSD has to be saved in the state you actually want.
- Editability ends
- Text becomes pixels. Smart objects lose their source. Vector shapes are rasterised at the document's resolution. This is a one-way door, so keep the PSD.
- Transparency survives
- Unlike a JPEG conversion, PNG has a real alpha channel, so a PSD with a transparent background stays transparent. This is usually the reason PNG is the right target for design work.
What is actually inside a PSD
A Photoshop document holds two quite different things. There is the editable structure: layers, masks, adjustments, text, smart objects. And there is a flattened composite, a plain raster image of how the whole stack renders.
Photoshop writes that composite so other software has something to show without implementing the entire rendering model. It is what Finder previews, what Preview displays, and what PixelFerry converts.
This is the honest description of the process, and it has a consequence worth being explicit about: the conversion reflects the file as it was last saved. If a layer was hidden at save time, it is not in the composite and no converter can bring it back.
Why PNG rather than JPG
For design work, almost always transparency.
A logo, an icon, a UI element or a cut-out product shot has an alpha channel, and PNG keeps it. Converting the same file to JPG flattens that transparency onto white, which is right for a photograph on a white page and wrong for a logo going onto a coloured background.
The second reason is edges. PNG is lossless, so the hard boundaries in typography and vector shapes stay crisp. JPEG’s DCT compression puts visible ringing around exactly those edges, and it is most obvious on the black-on-white text that design files are full of.
Colour, and the CMYK case
Print-bound PSDs are often CMYK, and this is the case to avoid. The bundled decoder reads the stored composite as 8-bit RGBA positionally. It does not consult the document’s colour mode, so a CMYK PSD is not remapped for screen, it is misread. Convert those in Photoshop.
The same decoder handles 8-bit composites only, so a 16-bit PSD fails rather than losing precision quietly.
Colour management does not survive this route either. The composite is handed to the encoder as a bare pixel buffer, so the document’s ICC profile is not carried into the PNG, unlike the HEIC and camera paths, where it is preserved. If the profile matters, export from Photoshop.
Converting a folder
Drop the folder in. PixelFerry walks it, picks up the PSDs and PSBs, and ignores what it cannot read.
Set PNG as the output. If the artboards are large, and design files usually are, set a max width in the same pass rather than writing 6000-pixel PNGs you will immediately resize somewhere else.
A large PSD is slow to decode, because the whole stored composite has to be read into memory before anything else can happen. The queue runs four at a time and each row shows that it is working, so a large file does not look like a hang.
When people do this
- Handing a developer flat assets from a design file without giving them the layered source or a Photoshop licence.
- Generating previews of an archive of old campaign files so you can actually see what is in them from Finder.
- Turning a folder of PSD mockups into images that fit in a slide deck, a wiki, or a client email.
What macOS already does
Preview.Preview opens PSD files and exports them to PNG, reading the same stored composite. It handles a multi-selection too, so for a handful of files it is perfectly adequate and already installed.
Where it stops being enough:The folder is large, or the artboards are. Preview keeps every open document in memory, and its export cannot cap the output dimensions of a 6000px artboard in the same step, so resizing becomes a second pass over files you have already written.
Limitations worth knowing first
- PixelFerry flattens to the stored composite. It does not render layers itself, so a PSD saved without a compatibility composite has nothing useful to read. Save with "Maximize Compatibility" on.
- A 16-bit PSD fails outright, the bundled decoder reads 8-bit composites only. A CMYK PSD does not fail; it is misread, because the decoder never consults the document's colour mode. Convert both in Photoshop.
- PSD and PSB are input-only. There is no route from a PNG back to a layered document.
PixelFerry requires macOS 14 (Sonoma) or later on Apple silicon and Intel. Conversion runs entirely on your Mac. No file, and no part of one, is uploaded anywhere.