I’m trying to create an application icon. I took a bunch of created *.ico files (one for each size) and combined them into a single *.ico file. I can see them all fine. I have 16×16, 32×32, 48×48, 64×64, and 128×128 icons (all 32bit w/ transparency).
However, when I build my app (a standard Windows Forms app written in C#) and look at the icon in Windows explorer, it looks fine at the first few sizes (up to 48×48 I think.. “Medium”), but if I use the “Large” or “Extra Large” display modes in Windows Explorer, I just see the 48×48 (I think) icon in an ever larger box.
How can I get Windows Explorer to recognize the larger icons? What am I doing wrong? Has anyone seen this issue before, and point me in the correct direction? I’m assuming there’s a problem with the way the *.ico file is built, or the formats… but I can’t find any hints anywhere.
As far as I understand it, once you get above a certain size (and it may well be 48×48), Explorer will go looking for a 256×256 icon, and scale it to the desired size.
128×128 is not a standard icon size, and Explorer may not bother looking for it. You can show icons at up to 256×256 in Explorer (“Extra Large icons”), though you can do sizes in between. If you size your icons to, say, 192×192, then it’s going to look better to take a large image and scale it down, rather than to take a small image and scale it up — so you’re better off adding a 256×256 image anyway, rather than a 128×128.