Image preview generation on opening folders gets aborted

[Marco-Jacobs]

Bug report

The preview generagion gets aborted on new folders after the first 4 or sometimes 5 Images. This problems exist as far as i could reproduce it on all NC 15.x Versions. With 14.x the pictures gets generated one after another.

Steps to reproduce

If you add a new folder with for example 10 images inside and open the folder in gallery view the 4 images for the folder icon gets generated. If you now open the folder, NC only shows these 4 pictures and the working circle disapears afer a few seconds. And 30 min later is still not a single picture more generated.

In this situation a reload of the folder doesnt chance anything.

If you now switch to the file list, all missing prewievs will be generated.

After that you can go back to the gallery view and all pictures will be shown.

Expected behaviour

After the first 4 images all other image previews will be generated. The same way as it is in the file list view and in NC 14.x.

Actual behaviour

The preview generation gets aborted.

Server configuration

Operating system: Ubuntu 18.04 LTS 64bit Web server: Apache/2.4.29 Database: MySQL 5.7.25 PHP version: 7.2.15

Nextcloud configuration

Nextcloud version: 15.0.5

Updated from an older installation or fresh install: updates every version since the first 15.x version

Client configuration

Browser: Google Chrome 72.0.3626 IE 11.648

Operating system: Windows 10 Ubuntu 18.10

Are you a developer willing to implement this feature?: developer yes but not much knowledge about the NC code

[Marco-Jacobs]

Additional Information

It seems, this problem doesn´t exist if the folder contains jpg files. In my example the folder contains dng files only. Maybe this is the key to solve it.

[godfuture]

I have the same issue with the thumbs in grid view. Rarely it finishes well, mostly it loads incomplete.

Nextcloud - 15.0.5 Gallery - 18.2.0

[skjnldsv]

Duplicate of #524