ICO je slikovna datoteka za ikone sistema Microsoft Windows. ICO datoteka ponavadi vsebuje eno ali več slik v različnih formatih in barvnih paletah.Ikone imajo lahko različne velikosti, paleto barv in transparenco.

Priporočljive vrednosti za ikone na Windows Vista operacijski sistem:

1. 256×256, 32-bit color, PNG compressed
2. 256×256, 8-bit color, PNG compressed
3. 256×256, 4-bit color, PNG compressed
4. 48×48, 32-bit color, uncompressed
5. 48×48, 8-bit color, uncompressed
6. 48×48, 4-bit color, uncompressed
7. 32×32, 32-bit color, uncompressed
8. 32×32, 8-bit color, uncompressed
9. 32×32, 4-bit color, uncompressed
10. 16×16, 32-bit color, uncompressed
11. 16×16, 8-bit color, uncompressed
12. 16×16, 4-bit color, uncompressed