Ideal size for .ico

Question

What is an ideal size for a .ico file, that would sit in the top corner of a window?

Ritter

Answer 1

Short answer: 16 x 16 pixels.

Long answer:

.ico files can actually contain multiple images, at multiple colour depths - you can provide 16x16, 32x32, 48x48 and 64x64 in a single file and the OS will pick the best one to show.

Of course to keep the file size low you don't want to put too many in there, but if you think people might be saving a link on their desktop (say it's a web application) then it's probably a good move.

Birdlime

16 x 16 might be stretched too much in high DPI. A 32-bit icon with 64x64, 32x32, and 16x16 sizes is only ~22k, so you should try to keep all different sizes and let the OS choose. – Nelidanelie

Upvoted! I didn't know that .ico files can actually contain multiple icons of varying sizes and that browsers would choose the best one. Thanks! – Schaaf

You can use the ConvertICO to bundle many png files into one ico file. – Nonmoral

Is it possible to do this in Photoshop? – Selfseeker

Gimp can do this – Dy

Answer 2

See Microsoft's recommendations.

Basically, 16x16, 32x32, 48x48, and 256x256 for application icons. I guess the window icon is a toolbar icon so 16x16, 24x24 and 32x32.

Decalcomania

Answer 3

To originally figure this out when wanted to start making .ico images I opened a good looking icon already being used in Windows 11 with GIMP. I found nine layers 256 128 64 48 40 32 24 20 and 16. So this is kind of the formula I've been following creating the icons in Gimp and none of my icons fail ever they always display no matter what size they are. With GIMP you can take any single image and turn it into a multi-layer icon, you just have to know how to do a bit of image editing.But it %100 free.

Diego

Creating too many layers will increase the size of the icon. That may block the browser from using it. – Carnarvon