Image - file previews not generated

Steps to reproduce

  1. upload images (.JPG), size differ from 2 MB to 15 MB
  2. open folder with images

Expected behaviour

Preview generated.

Actual behaviour

some previews are not generated, error shown in Image Viewer:
“Could not generate a preview of this file. Please go to the next slide while we remove this image from the slideshow”

I’m sure the files are there, because I can download them.

Server configuration

Operating system: shared hosting

Web server: Apache 2.4

Database: MariaDB 10.3

PHP version: PHP 7.3

ownCloud version: 10.3.2

Updated from an older ownCloud or fresh install: Fresh Install

Where did you install ownCloud from:

Signing status (ownCloud 9.0 and above): No errors have been found.

List of activated apps: admin config report, deleted files, federation, provisioning api, share files, update notification, versions, collaborative tags, comments, first run wizard, gallery, market, notifications

Are you using external storage, if yes which one: shared hosting storage

Are you using encryption: https for access

Are you using an external user-backend, if yes which one: no

Client configuration

Browser: Safari 13.0.4 or Chrome 79.0.3945.117

Operating system: MacOS Catalina 10.15.2

ownCloud log (data/owncloud.log)

Every image which has no preview has this log:

{“reqId”:“Xicc4KVupZ1u5b6RNH@6sgAAAAs”,“level”:3,“time”:“2020-01-21T15:46:40+00:00”,“remoteAddr”:“IPaddr”,“user”:“user”,“app”:“PHP”,“method”:“GET”,“url”:"/remote.php/dav/files/arnie/02.collections/File_0017.JPG?c=c00ad6c05dec4fa05d2f76a27aeb597c&x=64&y=64&forceIcon=0&preview=1",“message”:“Allowed memory size of 67108864 bytes exhausted (tried to allocate 24576 bytes) at /nfsmnt/hosting1_1/a/5/a57e93fa-3e86-4bd2-87ae-02c73cc75c8b/domain/sub/cloud/lib/private/legacy/image.php#514”}

Browser log

Browser console error: “Failed to load resource: the server responded with a status of 500 ()”

You receive plenty of results if you just do a simple web search with this string.
You need to increase your PHP memory limits.