Free online PNG to ACO converter

Some design workflows require an Adobe Photoshop swatch file rather than the original image, especially when a PNG is being used as a color reference. Converting it extracts selected or dominant colors into an .aco palette; it does not convert the PNG’s pixels into another image format.

What the PNG format is

PNG (Portable Network Graphics) is a raster format that stores pixel data with lossless compression. It supports indexed color, grayscale, RGB and RGBA color, and an alpha channel for transparent pixels.

Web browsers, screenshot utilities, scanners, and graphics applications such as Adobe Photoshop, GIMP, Krita, and Inkscape commonly create or use PNG files. Typical uses include logos, interface graphics, diagrams, screenshots, illustrations, and artwork with transparent backgrounds.

What the ACO format is

ACO is Adobe Photoshop’s color-swatches format. An ACO file stores reusable color definitions in spaces such as RGB, CMYK, Lab, and grayscale; newer ACO data can also include swatch names.

Photoshop loads ACO files into the Swatches panel, allowing their colors to be applied to text, shapes, fills, brushes, and other artwork. ACO is useful for reusing a palette across Photoshop projects and is normally much smaller than the source PNG because it stores color records rather than image pixels.

How to convert PNG to ACO

Using the built-in online converter

1. Open the PNG-to-ACO converter on 101convert.com. It can be used free without installing software.
2. Upload the source .png file.
3. Choose the available palette or color-extraction settings. A smaller palette produces fewer swatches; a larger palette preserves more of the PNG’s color variation.
4. Start the conversion and download the resulting .aco file.
5. In Photoshop, open Window → Swatches, open the Swatches panel menu, and choose the command for loading or importing swatches. Select the downloaded ACO file.

Creating an ACO file manually in Photoshop

1. Open the PNG with File → Open.
2. Select the Eyedropper tool and sample representative opaque pixels. Avoid anti-aliased edges, shadows, highlights, and partially transparent pixels unless those colors are intentional.
3. Open Window → Swatches and create a new swatch from the current foreground color. Add a descriptive name if required.
4. Repeat the sampling and swatch-creation steps for each required color.
5. Open the Swatches panel menu and choose Save Swatches. Save the palette as an .aco file.

Quality and compatibility limits

Palette extraction does not preserve the PNG’s dimensions, transparency, layers, paths, metadata, or visual arrangement. Keep the original PNG when the image itself is needed.

Pixels at transparent or anti-aliased edges can be mixtures of the foreground and background, producing unwanted swatches. Sample from solid interior areas. If the PNG contains an embedded ICC profile, color-managed applications can display or sample values differently from unmanaged software; retain the profile when color accuracy matters.

Automatic dominant-color extraction may select statistically common colors that are unsuitable for branding or production work. Review the generated swatches, remove incidental colors and duplicates, and verify important values against the source artwork. Photoshop generally provides the best ACO compatibility, while software that supports only RGB swatches may convert or omit CMYK, Lab, or grayscale entries.