Get the path of the cover photo

I want to get the path of the cover photo as I will export my entire database and need the paths of the cover photos too. like `C:\Users\user\Desktop\Songs\images\image001.png'

When I put the COVER in the columns, it shows one if it has a cover.

Where should the path be stored?
MP3tag will show you the files with EMBEDDED covers with the filter
%_covers% PRESENT
But these covers are embedded and therefore have the same path as the audiofile and cannot be seen in the file system.

It it possible to see also other files than music files if you add the corresponding extension in
Tools>Options>Tags

My target of this was that I want to know the name of the path of the cover photo so that I can add it to a database. Apparently this is not possible with the current system.

If the cover is embedded, then there is no path to a cover as this is "hidden" inside the audio file.
If you export the cover to a picture file in the file system, then this file has a path - but: as MP3tag usually does not treat picture files (except embedding or exporting them), it does not show them in the file list.
You would have to modify the settings for Mp3tag to load them, too.
Once you see the picture files, you can access the file properties, including the path.
So far it is not clear how you want to transfer the path information to the database (and whether you really need it when the pictures are embedded).

Problem is, I cannot find a suitable library that extracts ID3 TAGS (in php) in a nice way and always there are problems. Thats why I am using the exported list from the mp3tag software (as csv) and importing them to my db.

So if you use an export, you create one that deals with the file properties of picture files.
You only have to add *.jpg and *.png to the list in Tools>Options>Tags