Anyone who builds websites knows the little icon in the browser tab is called a favicon—but when it's time to actually make one, it's a hassle. ICO is an old format that most ordinary software doesn't even offer as an export option. You save a PNG with a screenshot tool, upload it, and the browser says the format isn't supported.
Converting an image to ICO isn't hard. An online tool gets it done in minutes, and can even generate all the multi-size icons a website needs. Here's how to turn an image into an ICO.
What Exactly Is the ICO Format?
ICO is the icon format used by Windows. A single ICO file can hold images at multiple sizes, and the browser or operating system automatically picks the right one depending on where it's displayed.
| Size | Common use |
|---|---|
| 16×16 | Browser tab favicon |
| 32×32 | Taskbar, Start menu |
| 48×48 | Desktop shortcuts, folders |
| 64×64 / 128×128 | High-DPI displays, app icons |
| 256×256 | HD icons, app stores |
So a proper website icon usually needs to contain several sizes like 16, 32, and 48—exactly the part that's hard to do by hand.
Which Source Images Convert Best?
| Source type | Suggestion | Why |
|---|---|---|
| Square PNG | Convert directly | No cropping needed, ideal proportions |
| Transparent logo | Convert directly | Keeps transparency, more polished icon |
| Rectangular image | Crop to square first | Avoids stretching distortion |
| Photo | Process before converting | Photos make weak icons; use a simple graphic |
Before converting, tidy up your source into a square, simple image—your icon will look much better.
Online Tool vs Professional Software vs Online Generator
| Comparison | Online converter | Pro icon software | Online generator |
|---|---|---|---|
| Ease of use | Low | High | Low |
| Multi-size export in one go | ✅ | ✅ | ✅ |
| Convert from an image | ✅ | ✅ | ❌ mostly drawing |
| Privacy | ✅ local processing | ✅ | ⚠️ some upload to cloud |
| Needs installation | No | Yes | No |
Practical Steps: Convert an Image to ICO with PixelForge
Open the PixelForge format conversion tool—no software to install, and images are processed locally in your browser, never uploaded to a server.
Step 1: Upload your source image Prepare a square image with a simple background (PNG is better since it can keep a transparent background).
Step 2: Choose ICO output Pick ICO as the output format, and the tool generates a properly sized multi-size icon file following website icon conventions.
Step 3: Download and use it Download the ICO, name it favicon.ico, upload it to your site root, and reference it in your HTML. Your icon will appear in the browser tab.
Summary
The key to converting images to ICO is "square source + one-shot multi-size generation." An online converter does it locally in the browser, saving you from installing software or assembling multiple sizes by hand.