Windows Icon File Extension. The ico file format is an image file format for computer icons in microsoft windows. Search more than 600,000 icons for web & desktop here.
There may be any number of reasons to change the icon of a certain file type. Remember to be careful and make sure that your source is safe. Might not be the most elegant solution (a noob solution, actually), but what i do is to create a temp empty file with the extension i want, than i use the method you showed above to get that file's icon, then i delete it.
For example, you may have a file named “document” that has the icon of your installed pdf reader.
Most icon packs are in.ico, but you’ll come across ones in.png. Actually windowsxp, server2003, and windowsxp64 all came with a file extension manager, simply named “extension manager”. It works great in windows 7, 8, and 10, and its interface makes changing icons for file types easy enough that you can run through a bunch at once if you need to. The icon will work for all icon sizes that are required on windows 10 however, the quality will depend on the original file that you uploaded.