Update screenshot references

Signed-off-by: Julius Härtl <jus@bitgrid.net>

README.md

@@ -5,8 +5,7 @@
 
 **A [Nextcloud](https://nextcloud.com) app integrating Collabora Online into your Nextcloud!**
 
-![](https://nextcloud.com/wp-content/themes/next/assets/img/features/collabora-document.png)
-
+![](https://raw.githubusercontent.com/nextcloud/richdocuments/master/screenshots/Nextcloud-writer.png)
 
 ## Development setup
 

appinfo/info.xml

@@ -21,11 +21,9 @@ You can also edit your documents off-line with the Collabora Office app from the
 	<website>https://collaboraoffice.com/</website>
 	<bugs>https://github.com/nextcloud/richdocuments/issues</bugs>
 	<repository type="git">https://github.com/nextcloud/richdocuments.git</repository>
-	<screenshot small-thumbnail="https://www.collaboraoffice.com/downloads/nextcloud/richdocuments/collabora-online-screenshot-for-thumbnail.jpg">https://www.collaboraoffice.com/downloads/nextcloud/richdocuments/collabora-online-screenshot-1.png</screenshot>
-	<screenshot>https://www.collaboraoffice.com/downloads/nextcloud/richdocuments/collabora-online-screenshot-2.png</screenshot>
-	<screenshot>https://www.collaboraoffice.com/downloads/nextcloud/richdocuments/collabora-online-screenshot-3.png</screenshot>
-	<screenshot>https://www.collaboraoffice.com/downloads/nextcloud/richdocuments/collabora-online-screenshot-4.png</screenshot>
-	<screenshot>https://www.collaboraoffice.com/downloads/nextcloud/richdocuments/collabora-online-screenshot-5.png</screenshot>
+	<screenshot>https://github.com/nextcloud/richdocuments/raw/master/screenshots/Nextcloud-writer.png</screenshot>
+	<screenshot>https://github.com/nextcloud/richdocuments/raw/master/screenshots/Nextcloud-spreadsheet.png</screenshot>
+	<screenshot>https://github.com/nextcloud/richdocuments/raw/master/screenshots/Nextcloud-presentation.png</screenshot>
 	<dependencies>
 		<nextcloud min-version="25" max-version="25"/>
 	</dependencies>