Shared image - Open Graph

[maprambo]

Steps to reproduce

1. Share an image
2. Send the public link i.e. via Telegram

Expected behaviour

The full image should be embedded (using the Open Graph Protocol).

Actual behaviour

Only a square preview of the image is shown, like it is shown in the file list in Nextcloud itself.

Server configuration

Operating system: Linux hp-server 3.19.0-68-generic #76~14.04.1-Ubuntu SMP Fri Aug 12 11:46:25 UTC 2016 x86_64

Web server: Caddy/0.10.2 (fpm-fcgi)

Database: mysql 10.0.29

PHP version: 7.0.18-0ubuntu0.16.04.1
Modules loaded: Core, date, libxml, openssl, pcre, zlib, filter, hash, Reflection, SPL, session, standard, cgi-fcgi, mysqlnd, PDO, xml, apcu, bz2, calendar, ctype, curl, dom, mbstring, fileinfo, ftp, gd, gettext, iconv, igbinary, json, exif, mcrypt, memcached, mysqli, pdo_mysql, Phar, posix, readline, redis, shmop, SimpleXML, sockets, sysvmsg, sysvsem, sysvshm, tokenizer, wddx, xmlreader, xmlwriter, xsl, zip, Zend OPcache

Nextcloud version: 12.0.0 - 12.0.0.29

Updated from an older Nextcloud/ownCloud or fresh install:

Where did you install Nextcloud from:

Signing status:

Signing status

[]

List of activated apps:

App list

``` Enabled: - activity: 2.5.2 - calendar: 1.5.3 - dav: 1.3.0 - federatedfilesharing: 1.2.0 - federation: 1.2.0 - files: 1.7.2 - files_automatedtagging: 1.2.2 - files_external: 1.3.0 - files_markdown: 1.0.1 - files_pdfviewer: 1.1.1 - files_retention: 1.1.2 - files_sharing: 1.4.0 - files_texteditor: 2.4.1 - files_trashbin: 1.2.0 - files_versions: 1.5.0 - files_videoplayer: 1.1.0 - firstrunwizard: 2.1 - gallery: 17.0.0 - impersonate: 1.0.1 - issuetemplate: 0.2.1 - logreader: 2.0.0 - lookup_server_connector: 1.0.0 - nextcloud_announcements: 1.1 - notifications: 2.0.0 - oauth2: 1.0.5 - onlyoffice: 1.0.4 - password_policy: 1.2.2 - provisioning_api: 1.2.0 - serverinfo: 1.2.0 - sharebymail: 1.2.0 - survey_client: 1.0.0 - tasks: 0.9.5 - theming: 1.3.0 - twofactor_backupcodes: 1.1.1 - twofactor_totp: 1.3.0 - updatenotification: 1.2.0 - workflowengine: 1.2.0

Disabled:

• admin_audit
• comments
• encryption
• systemtags
• user_external
• user_ldap

</details>

**The content of config/config.php:**
<details>
	<summary>Config report</summary>

{
"instanceid": "ocuugavv819x",
"passwordsalt": "REMOVED SENSITIVE VALUE",
"secret": "REMOVED SENSITIVE VALUE",
"trusted_domains": [
"REMOVED SENSITIVE VALUE"
],
"datadirectory": "/var/www/nextcloud/data",
"overwrite.cli.url": "https://REMOVED SENSITIVE VALUE",
"dbtype": "mysql",
"version": "12.0.0.29",
"dbname": "owncloud",
"dbhost": "localhost",
"dbtableprefix": "oc_",
"dbuser": "REMOVED SENSITIVE VALUE",
"dbpassword": "REMOVED SENSITIVE VALUE",
"logtimezone": "UTC",
"installed": true,
"mail_smtpmode": "php",
"mail_from_address": "cloud",
"mail_domain": "REMOVED SENSITIVE VALUE",
"loglevel": 0,
"appstore.experimental.enabled": true,
"theme": "",
"maintenance": false,
"trashbin_retention_obligation": "auto",
"htaccess.RewriteBase": "/",
"memcache.local": "\OC\Memcache\APCu",
"log_rotate_size": 104857600,
"auth.bruteforce.protection.enabled": true
}

</details>

**Are you using external storage, if yes which one:** Array
(
    [0] => \OC\Files\Storage\Local
    [1] => \OCA\Files_External\Lib\Storage\FTP
    [2] => \OC\Files\Storage\DAV
    [3] => \OCA\Files_External\Lib\Storage\OwnCloud
    [4] => \OCA\Files_External\Lib\Storage\SFTP
    [5] => \OCA\Files_External\Lib\Storage\AmazonS3
    [6] => \OCA\Files_External\Lib\Storage\Dropbox
    [7] => \OCA\Files_External\Lib\Storage\Google
    [8] => \OCA\Files_External\Lib\Storage\Swift
    [9] => \OCA\Files_External\Lib\Storage\SFTP
)


**Are you using encryption:** no

**Are you using an external user-backend, if yes which one:** LDAP/ActiveDirectory/Webdav/...

### Client configuration
**Browser:** Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_5) AppleWebKit/603.2.4 (KHTML, like Gecko) Version/10.1.1 Safari/603.2.4

**Operating system:**

### Logs
#### Web server error log
<details>
	<summary>Web server error log</summary>
	```
	Insert your webserver log here
	```
</details>

#### Nextcloud log (data/nextcloud.log)
<details>
	<summary>Nextcloud log</summary>
	```
	Insert your Nextcloud log here
	```
</details>

#### Browser log
<details>
	<summary>Browser log</summary>
	```
	Insert your browser log here, this could for example include:

	a) The javascript console log
	b) The network log
	c) ...
	```
</details>

[nickvergessen]

cc @MorrisJobke because you added it #1852

[MorrisJobke]

cc @MorrisJobke because you added it #1852

Yes - we for now only use the square images from the previews. So maybe we should adjust this, but on the other side also properly test if this looks still fine in all the other clients.

[rullzer]

PR in #7030