Project Icon: small vs large?

I am just about to set the icon for my application in the Projucer.

I saw that there are two icon types you can set: Icon (small) and Icon (large). See also attached screenshot.


Do I have to set both, or is it enough to set the large icon only?

What resolutions are recommended for large and small?


I normally just set the big one - the introjucer will create scaled copies as necessary.

The small one is just there for people who want to supply a tweaked version that'll look better at small sizes, but if your icon is pretty simple that's often not important.