The UZDoom Icon has BIG images (and others)

[Enjay]

Just out of interest, I was poking around looking at the UZDoom icon and I noticed that along with some smaller sizes that I don't normally see in icon files, it had some very large images.

It has:
16x16 256 colours
24x24 256 colours
32x32 256 colours
36x36 256 colours
48x48 256 colours
64x64 256 colours
128x128 256 colours
256x256 32 bit
512x512 32bit?
1024x1024 32bit?

Some of the smaller sizes are unfamiliar to me (I'm not sure I've seen 36x36 before, or maybe I have, but not commonly) but I assume they are maybe for non Windows operating systems?

However, the thing that really caught my eye was the 512x512 and 1024x1024 images. I've never seen images that big in an icon and the icon editor/browser I use (Greenfish Icon Editor) can only display them. If I try to save them, it tells me that they are too big and crops them to 256x256. It couldn't even confirm their colour depth (which is why I'm guessing 32 bit).

So, purely out of interest, just for the sake of knowing, I was wondering what the purpose of the unusual sized images was - particularly the really big ones. If they are present (which they obviously are) will Windows use them? Is it a Linux or Mac thing maybe? I did try googling information about icon image sizes, but I couldn't find anything conclusive.

[Blzut3]

macOS icns does indeed go up to 1024x1024 (512x512 scaled 2x for retina displays): https://en.wikipedia.org/wiki/Apple_Icon_Image_format I believe 36x36 also comes from the Apple ecosystem, although I don't know where it's used.

Linux is pretty flexible on sizing (one or more PNGs) including support for SVG. For rasters I believe typically third party apps just ship the largest size and let the system scale down (there are facilities for multiple prescaled images) and there's no particular size restriction there.

[Enjay]

That makes sense. Thanks for the information. I guess it's a weakness of the icon editor that I use that it doesn't support those bigger sizes properly. It's primarily intended for Windows icons though.

[bimshwel]

I remember when I played around with microangelo a lot I saw a 36x36 icon in SOMETHING and I wondered what that was about. I specifically recall that the original Age of Empires had a non-square (I now see it is 20x31) icon that got stretched into a square when it appeared on the start menu and I don't think microangelo would save that either, like trying to look at 24x56 AASTINKY in wintex. In any case I never heard of Greenfish Icon Editor and am glad to see that it works for that since I haven't had microangelo in years and haven't thought about looking up any icon editors lately either but like having one.

[Enjay]

I used to use Microangelo too. Greenfish is pretty similar in terms of interface and functionality.