XnView Software

XnView: MP 0.84
OS: Windows XP - 32 bit

When deleting an image file that is categorized in XnView using Windows Explorer, a ghost thumbnail is displayed in the file list when rebuilding thumbnails.

Effect: Irritating/wrong user interface

To reproduce:
1. In XnView browser, assign an image to one or several categories.
2. Switch to categories filter
3. In "Categories filter", select a category that is assigned to the image.
--> File list shows the image (correct)
4. Start Windows Explorer, navigate to the appropriate folder and delete the image.
--> File list still shows the image (not 100% correct, but o.k.)
5. Select View » Rebuild thumbnails
--> Actual behaviour (bug): Thumbnails are refreshed. For the orphaned category a grey thumbnail is displayed.

Expected behaviour: Not 100% clear: For the orphaned categories no thumbnail should be displayed.

if the thumbnail is not shown, the user can't remove it from categories for example

xnview wrote:if the thumbnail is not shown, the user can't remove it from categories for example

From my point of view, displaying dummy thumbnails for orphaned entires is not useful and irritating. What should the user do with this orphaned thumbnail?

Instead of displaying a dummy thumbnail, XnView should display no thumbnail at all. Ideally, XnView automatically removes the orphaned entry right away and thus correct this detected inconsistency.

@m.Th.: You're the categories and meta data expert. What would you suggest in this case?

Well, I cannot suggest too much... because the standard is here.

Displaying orphaned thumbs started a loooong time ago in the hey days of ACDSee when introduced for the first time the notion of "Offline media" - mainly CDs at that time but nowadays mostly external HDDs, clouds, LAN data etc.

From then many other programs (almost all?) display the 'offline thumbs' - the best ones having some sort of indication: a washed out appearance or a small icon in a corner.

All of these have the necessary tooling targeted directly to this situation: clean orphans, relocation engines etc. because having 'orphans' is unfortunately a necessary evil because the thumb is here and removing it is a decisive action hence it cannot be done automagically by the program.

There are storage architectures (one was mentioned just some days ago: http://newsgroup.xnview.com/viewtopic.php?f=82&t=34780 ) in which the user cannot or does not want to have all the data online. In fact we have such an architecture: a lot of scanned data at very high resolution (old manuscripts scanned page by page with a book scanner) which cannot be held all online. Then the only solution is such an architecture in which a program supporting offline data scans the actual data and when the thumb is found via filter/search/manually and clicked then the program requests the media with the recorded label or serial number.

As we see, we have as a premise that "Ok, they are orphaned but perhaps we can find their parents through an action" (bringing the media online again). If this isn't the case, then we can safely delete the orphans via tooling discussed above.

In the topic at hand, the things get more murky because Rebuilding is a decisive action. However, the same principle still applies here: "They are orphaned but perhaps we can find their parents" (undelete, undo a move action, reconnecting to media etc.). That's why I think that the actual behavior is normal.

Just to be sure that the program allows the deletion of the orphaned thumbs via Del key and/or "Tools | Settings | Optimize..." subsystem.

Thank you for this long and good explanation, m.Th.. I understand now that this grey thumbnails are needed as placeholders for files that are (temporarily) not available.

Though, something seems to be going wrong:
After testing I have many categories in the categories filter which indicate that image files are assigned. But when clicking on them, there are no grey thumbnails. According to your explanation this is a bug, right?

Though, something seems to be going wrong:
After testing I have many categories in the categories filter which indicate that image files are assigned. But when clicking on them, there are no grey thumbnails. According to your explanation this is a bug, right?

Well, it is a bug...

...but rather is not a bug - it is worse: it is a mess.

There are different layers of development in the program which give it an inconsistent behavior: sometimes as online-only DAM, other times with offline capabilities. Ok, perhaps not with a full range of offline tooling but enough in order to be quite useful... ...if it were ok.

I would suggest to fix these inconsistencies and provide a streamlined UX of an offline browser which in our case now is much easier to achieve, rather than having „Garbage collectors” to hide the offline data which still linger in the database.

In this case, indeed I think that it is much easier to put some gray thumbs for the offline results of a DB query (filter, search, copy/paste to address bar of an already cataloged path etc.).

m.Th. wrote:... In this case, indeed I think that it is much easier to put some gray thumbs for the offline results of a DB query (filter, search, copy/paste to address bar of an already cataloged path etc.).

Thanks for your explanation, m.Th.. Instead of just a grey icon I'd suggest to have a "offline" thumbnail indicating that the file is currently offline (just a grey thumbnail looks like a bug and not like a real feature).

Instead of just a grey icon I'd suggest to have a "offline" thumbnail indicating that the file is currently offline (just a grey thumbnail looks like a bug and not like a real feature)

The standard practice is to have the thumbnail should stay „as is” just to have something distinctive rendering. A greyed (or other color) border, background or a small icon in a corner. This is important because we want to see what we lost in order to decide if we want the „lost” photos back or not.

m.Th. wrote:

Instead of just a grey icon I'd suggest to have a "offline" thumbnail indicating that the file is currently offline (just a grey thumbnail looks like a bug and not like a real feature)

The standard practice is to have the thumbnail should stay „as is” just to have something distinctive rendering. A greyed (or other color) border, background or a small icon in a corner. This is important because we want to see what we lost in order to decide if we want the „lost” photos back or not.

Hmm, this would require that catalog and thumbnail cache always have the same contents. There's the setting "Always exclude removable drives" in Settings | Browser » Catalog | Excluded/Included so having the same contents in both catalog and thumbnail cache might not even apply today - but I'm not sure, here.

Hmm, this would require that catalog and thumbnail cache always have the same contents.

Not really - just a stable state between the two. It there is an (offline) entry in the catalog then try to display the thumbnail. If the thumbnail is present then display it accordingly with the 'offline' flag or not.