ICO Generator

Converts one uploaded image into four fixed square sizes (16x16, 32x32, 48x48, 128x128) and lets you download each as either a standalone PNG or a real Windows .ico file. The ICO is assembled in-browser by writing the ICONDIR/ICONDIRENTRY headers around a single PNG payload, so no server or native binary is involved.

1. Click the file input and choose any image (the input accepts image/*). 2. Click Generate ICO Sizes — four preview cards appear. 3. For each size, click PNG to download <name>-<size>x<size>.png, or ICO to download a true .ico file with the same name.

Each .ico embeds exactly one PNG entry: a 6-byte ICONDIR header, a 16-byte ICONDIRENTRY (width/height clipped to 0 for >=256, planes=1, bit count=32), followed by the PNG bytes from the canvas. Output filename is derived from the uploaded file's base name.