How can I learn about Catalog and Metadata settings?

[OldPilot]

I am most confused and could use some direction/help to where I can read and understand the catalog and database management. In settings>Catalog I see directories that no longer exist on my system. All these indicate a number of files, but some show size of content and some show 0 size. I have tried optimize, nothing happened. I assume sometime in the past I moved these directories using drag and drop in windows. The files now reside in same named folders on another drive. What have I done wrong that causes this to happen? Why doesn't optimize clean it up?

Another question about 'base path' , What does this do? I have seen comments about being careful with this, but I have no idea what it does. My base path is "\". Is there a manual reference that will explain how I should operate the catalog?

Also, maybe related, are select boxes in settings>metadata. On mine only the "Import" box at top is selected. But, "export" is not selected. What does all this mean? Somewhere I can read about this and what the options do.

I ultimately want to have images (estimate 3K - 5K) annotated with metadata names, captions, dates within the files and able to put on external/flash drive for distribution to family members and decedents so they can have the images and the information. I would like for them to have Xnview to see the images and to view the data I have put in. I would not want to transfer images to external drive and later learn that the data I entered did not transfer because I made a catalog error.

[michel038]

Hi,
Some answers in this message
viewtopic.php?p=179720#p179720

Regarding "Base path", if you are using xnviewmp on a single PC and your photos are on a local disk, do not change this field and leave the default value "\"
After years of reading this forum, i still do not understand completly how to use base path feature.

About Catalog management.
First consider backing up your catalog by copying xnview.db to a safe place (when xnviewmp is closed)
The next step is to make sure that useful informations contained in the catalog wont be lost during hazardous operations.
Maybe you should first enable export options , select bunches of JPG photos, and use "View > Update files from catalog", so that keywords, ratings, labels will be copied into xmp and or iptc metadata.
Then you will be able to clean the catalog by deleting entries for non existing folders ... etc

Photos with embedded iptc or xmp metadata can be sent to other persons. They will have to use a software that can use metadata, such as microsoft photos or xnviewmp, or any other

[OldPilot]

The next step is to make sure that useful informations contained in the catalog wont be lost during hazardous operations.

I did not know it was possible to have metadata not in the image file itself. Can I rely on xnview to tell me that a particular piece of data is recorded in the file versus just being associated with the image but located somewhere else?

Thanks Michel for giving me the link to the other informative post. It looks like I can spend some amount in absorbing that one.