ICO generator

Turn a PNG, JPG or WebP into a multi-size .ico icon file right in your browser, no upload.

How to make an ICO file

  1. Drop or pick a PNG, JPG or WebP image (a square image works best).
  2. Choose which icon sizes to include — 16, 32 and 48px cover most uses.
  3. Create the .ico and save. It bundles every size in one file.

What is an ICO file for?

The .ico format packs several sizes of an icon into a single file, so Windows and browsers can pick the sharpest one for each spot — a 16px tab icon, a 32px taskbar button, a 48px desktop shortcut. OptImg renders each size with a high-quality resampling filter and packs them into an .ico that works everywhere, all on your device with nothing uploaded.

Frequently asked questions

Are my images uploaded to a server?
No. The image is decoded, resized and packed into an .ico entirely in your browser: nothing is uploaded and your file never leaves your device.
Which sizes should I include?
16 and 32px are used by browser tabs and taskbars, 48px by Windows desktop shortcuts, and larger sizes (64–256px) by high-DPI displays. Including 16, 32 and 48 covers the vast majority of uses.
My image isn't square — what happens?
It's centre-cropped to a square before resizing, so the icon isn't stretched. For full control over framing, crop it to a square first with our Crop tool.
Do I need a favicon package instead?
If you're setting up a website, the Favicon Generator produces the .ico plus the PNG icons, web manifest and the exact HTML to paste. Use this ICO tool when you just need a standalone .ico.
Why not just rename a PNG to .ico?
Because the extension is not the format. An .ico file has its own container structure: a small directory at the start listing each image it holds, its dimensions and colour depth, followed by the image data itself. Renaming leaves a PNG with a misleading name, and anything that actually parses the file — Windows Explorer, an installer, an older browser — will reject it. Some modern browsers tolerate a PNG served as a favicon, which is why the trick sometimes appears to work, and then fails in exactly the places that matter.
Does an ICO file keep transparency?
Yes, when the source has it. Transparent corners are what make a rounded logo sit correctly on a dark taskbar or a light desktop rather than inside a visible box. Start from a PNG or WebP with a real alpha channel; a JPG cannot carry transparency, so a JPG source produces an icon with a solid background.
What makes a good icon at 16 pixels?
Ruthless simplification. At that size you have roughly the detail of a single letterform, so a full logo with wordmark turns into grey mush. Take the most recognisable element — a monogram, a symbol, a distinctive shape — and let it fill the frame edge to edge. Strong contrast against both light and dark backgrounds matters more than colour accuracy, and thin strokes disappear entirely, so thicken them before generating.
Where does the .ico file go on a website?
Traditionally at the site root as favicon.ico, which browsers request automatically even without any HTML pointing at it. That automatic request is the reason the format is still worth producing: it is the fallback that works when nothing else is configured. Modern sites usually also declare PNG or SVG icons in the page head for higher-resolution displays, and keep the .ico purely as the safety net.