XnView Software

Is there no possibility to update the whole xnview-catalog from all the existing images?
What is "Ansicht > Katalog aus Dateien aktualisieren" really doing?

Dear Pierre
is there no possibility to update the whole xnview-catalog from all the existing images?
If its no, please tell it to me.
If its possible please tell me in which way.

First, backup your XnView.db file, by copying it elsewhere.

1) If all your categories are written as XMP hierarchical keywords, if stars rating and color labels are stored as metadata you can delete the catalog :
Got to Settings, Catalog, and delete the whole table . See in "Categories Filter" window, if all your categories are empty. Elsewhere, you can close xnviewmp and delete or rename XnView.db .

Then , in Settings, Metadata , ensure that first option, "Import" , is enabled. Go to Settings, Catalog, use "Add Folder" button, and select the parent folder of your photos. This will take about 1 min for 1000 photos.

I think "tags" can be lost ( tags are not keywords here, tagging is an internal feature of xnviewmp, a photo is tagged or not) I don't know where tags are stored, maybe in the db file ?

OR

2) If your keywords are IPTC and hierarchized, set the "Read hierarchical keywords" option in settings metadata, with the character used as separator.
3) If there is no hierarchy in your keywords, you will loose the hierarchy, flat keywords often generate flat categories
4) Star ratings were stored in EXIF data inthe past, and in XMP metadata if you enabled the option. I think I remember that Color labels can be stored in IPTC and XMP. It's useful to check all this if you fear loosing stars and colors.

You can first export the names of all your categories as a TXT file (= thesaurus or keywords dictionnary) : "Categories management, Export" in categories pane ; you can also clean categories before creating (import) the new database, but it's not very useful.
You can also export links between photos and categories by using : "File's Categories, Export" , this will generate a XML file as a backup of a part of the DB file.

I hope i didn't forget anything

Thank you for the instructions. Unfortunately, I only saw the answer these days - apparently I was unsubscribed from the topic subscription.

I have now tried the procedure on a few test files or folders. In principle, it works as expected. Two more questions:

1.
In which image formats can XMP or IPTC keywords be written?
In Settings/Metadata I ticked:
- Import XMP/IPTC keywords
- Export categories to XMP/IPTC keywords
- Create XMP metadata
- Create IPTC metadata
This also works for JPG, TIF, PNG, but not for other image formats (BMP, GIF, PSD ...).
Can the "Export/import categories of file" function be helpful here?

2.
What is the difference between "base path of your images" and the "added" folders?

In which image formats can XMP or IPTC keywords be written?

It's difficult to answer ...
You can read "supported file types" for exif,iptc, xmp, ICC fields here : https://exiftool.org/
In many cases, XnViewMP does not use exiftool, but one can learn there which file types can't use embedded metadata.

Another way is to use "sidecar files" : these companion files can contain XMP metadata for any file type.
You can generate a xmp sidecar file by ticking "create sidecar" in metadata settings, and
-select a file , unmark / mark it's category , release selected file.
Result : a .xmp file is created, containing xmp data (categories, stars...)
- if you want to create a large amount of sidecar files, use categories filter
- select a category in the filter, select all files shown, unmark / mark the category (in categories pane) , unselect files, .xmp files are created.
- when using xmp sidecar files, each photo needs it's own companion to keep categories or other metadata.

Can the "Export/import categories of file" function be helpful here?

For file types that do not support embedded metadata, yes. First, it's a backup for your categorizing work.
You can install a new instance of PORTABLE xnviewmp somewhere in your PC, when it starts, choose "in program folder" for settings to be stored.
Then export file's categories of first xnviewmp (a xml file), and import it in the second xnviewmp, in order to check if it's a good solution for your specific usage.
( Before importing, you could edit and clean the xml file if necessary or if you need to move photos ...)

What is the difference between "base path of your images" and the "added" folders?

Added folders : when "import" settings are enabled, xnviewmp reads metadata of specifed folders to update it's database (catalog)
Base path : I don't use it, because some bugs occured with this some years ago.It describes the path to the main folder for photos.
I think it can be used to use a shared database, or shared photos in a server.