Why do some .ico files look blurry in Windows?

Because they contain only one resolution. Windows then has to scale that single image up or down for every context it needs an icon in, and scaling a 16-pixel image to 256 looks terrible. An ICO with all the sizes in it never has to be scaled.

What size PNG should I start from?

At least 256×256, and square. Everything is generated by scaling down from the largest layer, so starting small limits how good the big one can be.

Does it have to be square?

It should be. A non-square source has to be padded or cropped to fit an icon's square grid, and neither gives you what you probably intended.

Can I use this for a favicon?

Yes — a multi-resolution .ico is still the most compatible favicon there is, and browsers pick the size they need from it.

Free converter

PNGICO

PNG to ICO Converter

Most converters hand you an .ico containing one image, and it looks wrong everywhere Windows actually uses an icon. A real ICO is a container of several sizes — Windows picks the right one for the taskbar, the desktop, the folder view and the title bar. PhotoTray writes all of them.

Download for Windows

Windows 10/11 (x64) · Free · No account

Drop in your files — ICO files land in the folder you pick, containing 16, 32, 48 and 256 pixel layers.

Why convert

Why a multi-resolution ICO matters

An icon file is not one image. Windows asks it for a 16-pixel version in a title bar, a 32-pixel one in the taskbar, and a 256-pixel one in a large folder view — and if the file only contains one size, Windows scales it and the result looks blurred or aliased depending on which way it had to go. Containing every size is the entire reason the ICO format exists.

An application icon for a Windows program you are building or packaging.
A favicon that looks right in browser tabs and bookmarks.
A custom folder or shortcut icon.
Replacing a blurry single-size .ico someone else generated.

How it works

Convert PNG to ICO in a few clicks

1
Drop in a square PNG
Start from at least 256×256 so the largest layer is sharp. A transparent background is normal for an icon.
2
Choose ICO
PhotoTray generates the 16, 32, 48 and 256 pixel layers and packs them into one file — there is nothing to configure.
3
Get a proper icon back
One .ico containing every size, which Windows can choose from correctly at any display scale.

The details

PNG to ICO, at a glance

Engine: sharp (libvips) for scaling, to-ico for the container
Sizes written: 16, 32, 48 and 256 pixels, all in one file
Transparency: Preserved in every layer
Best input: A square PNG of at least 256×256
Where it runs: Your own PC — nothing is uploaded
Platform: Windows 10/11 (x64)

Questions