What's the [1] behind the basename on the title bar?

[TheCGDF]

When open picture on my Android phone, there will be a [1] behind the basename:

Sometimes it will be [2].

The raw name does not have [1]:

It is not related to the index of pictures, it is still [1] when I open second picture.

[fire-eggs]

This is Microsoft. Windows Explorer actually makes a copy of the file to your local machine and adds the [1] to it. If you're seeing [2] it's because you have two files with the same name in the place where Windows Explorer copied it.

If you turn off the "Display basename" option in ImageGlass settings, you'll see the full path of where Windows Explorer copied the file. For example [me viewing a file on my Android tablet]:

[TheCGDF]

Okay... Thank you. It's so weird...

[fire-eggs]

Yes, it's very weird.