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Image to ICO

Repack a PNG or JPEG into a genuine multi-size ICO file, with the directory and payloads written byte by byte.

Convert an image to ICO

Download ICO
Sizes written: load an image to begin
Structure: a 6 byte ICONDIR, one 16 byte entry per size, then the payloads
Small sizes are stored as uncompressed 32 bit BMP payloads and 256 px is stored as PNG, exactly as Windows expects.

How to use the Image to ICO

  1. Load the PNG or JPEG you want to turn into an icon file.
  2. Choose which pixel sizes to embed and a background for the BMP images.
  3. Click Build ICO, then download the finished favicon.ico file.

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Frequently Asked Questions

Common questions about the free online image to ico.

Load the PNG, choose the sizes you want, click Build ICO and then download the file. The result is a real multi-size icon file.
It can embed 16, 32, 48 and 256 pixel images. The 256 pixel image is stored as PNG and the smaller ones as BMP payloads.
Windows Vista and later allow PNG data inside an ICO, which keeps the large icon small. Older readers only expect BMP data.
A six byte ICONDIR header holds the image count, then one 16 byte ICONDIRENTRY per image gives the size, bit depth and payload offset.
The 256 pixel PNG keeps transparency. Smaller BMP sizes are flattened onto the background colour because their payload has no alpha.
Use a square PNG of at least 256 by 256 pixels with a simple shape, otherwise the 16 pixel icon will look muddy.
No. The file is decoded and the ICO bytes are assembled in your browser, so the image never leaves your device.
Yes. Name it favicon.ico and place it in the site root, or reference it with a link tag in the page head.
Yes. The converter runs in any modern mobile browser and writes the icon file straight to your downloads folder.

Last updated: October 10, 2026