How to Open and Convert ICO Files

Why ICO doesn't behave like a picture

The main source of confusion is that ICO is a container, not a single image. Inside it usually sits several versions of the icon at different sizes: 16×16, 32×32, 48×48, sometimes 256×256. We cover how the format works in "What Is ICO".

Because of that, a normal viewer either won't open the file or shows just one size from the set. ICO is also historically tied to Windows: macOS and Linux may have no built-in tool for it at all. The good news is that opening and converting an ICO today is easier than it looks.

The fastest way: browser and online

Browsers can display ICO because it is the favicon format. So the quickest view is this: drag the .ico file straight into a browser window and it shows the picture. Downside: you only see one version and can't conveniently save it at the size you want.

For a full result — seeing all sizes and saving them in a normal format — use an online ICO-to-PNG converter. It unpacks the container, returns the image with transparency, and works the same on Windows, macOS, Linux and even a phone.

Windows: viewing with built-in tools

On Windows a double-click on an ICO most often opens the Photos app — which shows the icon. If the association is broken, right-click → "Open with" and pick a viewer. That is fine for just glancing at the picture.

But built-in tools won't let you extract individual sizes or edit the icon. For that you need either an editor or a conversion. By the way, to set an ICO as a folder or shortcut icon, you don't open the file — you point to it in the shortcut's properties ("Change Icon").

Photoshop, GIMP and Paint.NET

If you actually need to edit the icon, the choice depends on the editor:

• GIMP — opens and saves ICO out of the box, and can show and edit each embedded size separately. The most convenient free option for icon work.
• Photoshop — doesn't understand ICO by default. You need the free ICOFormat plugin; once installed, ICO opens and saves like a normal file.
• Paint.NET — supports ICO via a free plugin (IconCur), after which it too works with the sizes inside the file.

Conversion: ICO ↔ PNG/JPG

Conversion is the universal key to ICO. It solves both jobs: "view/extract" and "edit and pack back." The logic is simple:

The format choice in step one is easy: PNG if you need transparency (icons almost always do), and JPG if transparency doesn't matter and a minimal file size does — for a preview, say. For JPG, the ICO to JPG converter helps.

Which method to choose

To keep it straight, here's a quick cheat sheet:

• Just look → drag the ICO into a browser or open it in Photos.
• Pull out a logo, see all sizes → the ICO to PNG converter.
• Edit properly → GIMP (or Photoshop with a plugin), or edit the PNG after conversion.
• Make an app/site icon → pack it back via PNG to ICO.

If you are instead building an icon from scratch, start with the "How to Make a Favicon" guide. And the full list of conversions is always on the all formats page.