Is it useless to have icon sizes other than 32 & 256 in Win11 on the desktop?

Just moving to Win11 now, as there's no compelling reason to do so. Anyway, I have a lot of custom icons I like to replace standard Windows stuff with, so I deployed my first one to the Recycle Bin today. I have a full suite of sizes in the relevant (single) *.ico file, 16/24/32/48/64/128/256, but Win11 is doing a terrible job of using them. As I change resolution back and forth to test the issue, in fact, the OS seems fixated on 256x256 and 32x32 and doesn't want to use any of the other sizes. After some random size changes where it stayed with the 256x256 version even as I went down to about half my monitor's capability, the ultimate test was when I took the monitor down to its very lowest resolution, 800x600, scale set to 100%, desktop preference set to small icons, and it still only went down to 32x32. Not 24x24, let alone 16x16. I know those are usually taskbar icons, but still--800x600 with preference to small? Holy cow. Right now I switched it to 1280x1024, still 100% scale, set to medium icons, for which you'd think it would use 32x32 or maybe 48x48, but nope, it even jumped over the 64x64 and is using either 128x128 or 256x256 (can't tell which of those; image is compressed too small) and drastically scaling the image down. And this behavior is not some random screwup that will be solved by a restart, because I DID restart--and it's still doing it.

So I'm coming to the conclusion that in Windows 11, if creating custom icons you might as well just do a 32x32 and a 256x256 unless you know for sure you're going to use the icon on the taskbar or toolbars. Or is my experience anomalous? I'm jumping straight from Win7 to Win11, so I have no idea how 8-10 did with icons, but Win7 certainly used sizes more fluently.

*bump* Would it be possible for others to either confirm or disconfirm my experience? Is this something anomalous with my new laptop, or is it a more widespread phenomenon?

I don't know if this is normal or not... but you might trying clearing the icon cache after changing resolutions. See if it reloads with a more appropriate size.

Developer guidance on when various icon sizes are used…

Levitate--thanks for the suggestion, but this is a brand new clean-install of Win11 and this was one of the very first things I tried to do, getting it customized to my liking. So I'd assume that there won't be any real icon cache to clear. Should I still try this?

Pseymour--thanks a ton for the link. That's the sort of theoretical info I've been missing.

pseymour, following up on your linked page, can you please confirm whether I'm understanding correctly?

If I want to, say, use Greenfish to create a custom icon in a *.dll to inject into a favorite piece of freeware which won't get arbitarily updated by Windows (thus suddenly reverting back to the original icon), I don't just need the bare minimum of 16x16, 24x24, 32x32, 48x48, and 256x256 icons. I was already doing that and adding 64x64 and 128x128. But really, for decent Windows downscaling, you have to go far beyond a single instance of your icon at these sizes. You must also...

1. Add icons of sizes 20x20, 30x30, 36x26, 40x40, 60x60, 72x72, 80x80, 96x96. These do not have to be present for the *.ico file to be used, but if you don't furnish them, Windows will downscale unreliably. Even when it should be downscaling from, say, the 96x96 image, Windows might instead continue to downscale the 256x256 image--that's what my experience suggests. However, if you have every single one of the sizes Windows wants, it will use the sizes more accurately.

2. Inside the *.dll file, Windows looks for images that have a particular naming syntax: the icon must have the parameters "AppList", then dot, then "targetsize", a hypen, then a decimal number indicating image size. Maybe if the original images weren't named according to this schema, Windows gets confused and doesnt use the icon effectively. Since you can't see the names once you pack images into a *.dll, at least not in Greenfish, you need to name your images according to this syntax before you put them into your *.dll--although that's impossible to do in Greenfish if you create the images in the image editor itself rather than importing them from outside; there's no way to name your separate images--so maybe I really don't understand what's going on here. Although you can create an icon *.dll with prenamed images with Resource Hacker. Also, maybe the document is assuming that in an application (as opposed to an *.ico for the Windows system) you should just use naked *.png files rather than putting them into a *.dll. Can you offer some clarification on this?

3. Provide not just one but 3 separate *.dll files (or separate sets of standalone *.png images) with these sizes. One set will be your base, but you must also furnish icons intended for the light and dark themes. If you do not furnish the two additional files for light and dark themes, Windows will get confused and scale your icons much more arbitrarily than it otherwise would (that's what I gather from the statement, "your icon will scale to a smaller size".

4. The way Windows tells which icons are for which theme is by looking at the filename, where an additional ending parameter indicates light or dark, and the absence of such a parameter indicates base. If the image is to be used for the dark theme, it must end with "_altform-unplated"; if the light theme, "_altform-lightunplated".

So presumably if you follow all of these conventions, Windows does its best to pick correct sizes but could be making mistakes at any point during the process when it doesn't see what it's looking for, either in terms of naming syntax or the "extra" sizes.

But that's all for application icons. What about the problems I'm having with a system icon in an *.ico? Since these are packed in *.ico files, I assume we have to disregard the naming syntax. Can you confirm that Windows does NOT look for this syntax inside of *.ico files being used in the system, as in my case where I'm trying to replace the standard Recycle Bin icon?

What might certainly be a problem is...

1. Lacking the supposedly optional sizes between the required sizes.

2. Lacking three different *.icos, one for each of the three themes. In this case, is there a special syntax for the *.ico filename, as the individual image filenames are irrelevant? If that is the case, I assume that it would follow the individual PNG syntax except size would not be involved, so where the number goes, you'd put a distinguishing descriptive name, e.g. "AppList.targetsize-MyRecycleBin,ico". Then the dark-theme file would be "AppList.targetsize-MyRecycleBin_altform-unplated,ico".

Also, does Windows try to intelligently discriminate between the actual lightness and darkness of icon images to really verify that the icons will work in light/dark theme? I assume not, which means that I could mollify Windows and avoid any stutters by providing the two additional appropriately named *.ico files but not actually changing the images, as I never use the light or dark themes so changing the icons for them would be wasted time.

Many thanks if you can clarify these issues for me.

schmibble said:

Levitate--thanks for the suggestion, but this is a brand new clean-install of Win11 and this was one of the very first things I tried to do, getting it customized to my liking. So I'd assume that there won't be any real icon cache to clear. Should I still try this?

Pseymour--thanks a ton for the link. That's the sort of theoretical info I've been missing.

Click to expand...

Probably won't help, but won't hurt either.

Rebuild Icon Cache in Windows 11 . Be sure to note posts #26 and #47 in the thread.

I seem to recall I also had to set protections to get into the folder to do this. But that's foggy :- )

Levitate, thanks for the link and heads up about the two posts. I'd probably have been caught by #26 so especially appreciate that, and the knowledge in 47 is good--you can never tell when you might need to know what Windows is doing under the hood.

*bump*
@pseymour, or heck anyone else who has the knowledge--I was just wondering if you could respond to the various clarification questions I asked after I (very carefully) read the Microsoft doc to which you linked. I'd be most grateful.

And in addition, one more question--in that documents table of Microsoft scale factors, neither the Desktop nor the inside of standard directories are mentioned, yet those are frankly the two most common places I see icons: when I'm looking in folders and messing around on the desktop. So do you know which use-cases would apply to 1) the desktop, and 2) the inside of folders? Here's the tabel so you needn't actually review the document:


My guess would be that folders would go in the context-menu use-case and the desktop would go with the Taskbar use-case, but I have no way to tell. It would be really helpful to know because if I'm creating an icon that is only going to be used on the desktop--to replace the shipping Recycle Bin, for example--then I could just produce sizes pertaining to that use-case.