Windows 11 no longer shows thumbnail previews for folder icons by default. Instead, a little white bar on the folder icons confirms the folder has content.
In this case, it becomes difficult to find the right folder among many identical yellow folders and the only way is to search by name or modified date. It may dramatically decrease your productivity.
With FolderIco you can fully customize the folder look. You can use predefined icons from many libraries or create your own with any color or image. But the main feature for Windows-11 users is the ability to create folder icons with the covers, here is how it looks. New folder thumbnail looks even better than previous standard previews.
Right-click onto the folder you want to create the preview and choose the "Change Folder Icon->More Icons" menu item. (Make sure you already installed the FolderIco app.)
At the opened dialog select the "Create" category at the left and click the "Add Cover" button, then browse for the image you want to set as the folder cover.
That's it, just click the Ok button and the selected folder will have a unique look with the image which you set.