Support intro
Sorry to hear you’re facing problems 
help.nextcloud.com is for home/non-enterprise users. If you’re running a business, paid support can be accessed via portal.nextcloud.com where we can ensure your business keeps running smoothly.
In order to help you as quickly as possible, before clicking Create Topic please provide as much of the below as you can. Feel free to use a pastebin service for logs, otherwise either indent short log examples with four spaces:
example
Or for longer, use three backticks above and below the code snippet:
longer
example
here
Some or all of the below information will be requested if it isn’t supplied; for fastest response please provide as much as you can 
Nextcloud version (eg, 12.0.2):
Operating system and version (eg, Ubuntu 17.04): Windows 10 Professional
Apache or nginx version (eg, Apache 2.4.25):
PHP version (eg, 7.1):
–> I am using Nextcloud via the web interface (Firefox 71, also tried with Edge and Brave), hosted by wölkli. I looked through the options and have no idea where to find the information above, maybe you can give me directions ?
The issue you are facing:
I have lastly created a Nextcloud account, hosted by wölkli in order to host and share photos. I created a folder, uploaded 30Mb of jpg files, a bit more than 1Mb each. I can download a read them. However, when I’ve tried to see the pictures online, via the files browser or the gallery app, I have been getting the same answer for every file : “Error! Could not generate a preview of [name]”. EDIT 22/12 : I’ve just noticed that 3 jpg files weighing about 500kb can be previewed. Is there a maximal size for seeing pictures in Nextcloud ?
Is this the first time you’ve seen this error? (Y/N):
Yes, as this account is new.
Steps to replicate it:
It happens every time I try to open a file or upload and open a new file.
The output of your Nextcloud log in Admin > Logging:
PASTE HERE
–> I am using Nextcloud via the web interface. I have no idea where to find these information, maybe you can give me directions ?
The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):
PASTE HERE
–> I am using Nextcloud via the web interface. I have no idea where to find these information, maybe you can give me directions ?
The output of your Apache/nginx/system log in /var/log/____:
PASTE HERE
–> I am using Nextcloud via the web interface. I have no idea where to find these information, maybe you can give me directions ?
