wallabag: If you change the URL of your wallabag instance, all links to local images are broken

Issue details

When the option Download images locally is on 1 (in Internal Settings → Misc) and if you change URL of *your* wallabag instance , all links to local images are not changed to the new setting, so they are all broken.

Environment

• wallabag version (or git revision) that exhibits the issue: 2.2.1
• How did you install wallabag? Via git clone or by downloading the package? make update
• Last wallabag version that did not exhibit the issue (if applicable):
• php version:
• OS: raspbian
• type of hosting (shared or dedicated):
• which storage system you choose at install (SQLite, MySQL/MariaDB or PostgreSQL): sqlite

Steps to reproduce/test case

1. Lets say your URL is http://wallabag.name.tld
2. In internal settings → misc → URL of *your* wallabag instance 1bis. Put: http://toto.name.tld
3. Add an article 2bis. Notice you have a 404 error with images because links begin with http://toto.name.tld
4. Back to internal settings → misc → URL of *your* wallabag instance 3bis. Put: http://wallabag.name.tld
5. Back to the previous article: your images are still 404 4bis: Note links for images are still with http://toto.name.tld instead of http://wallabag.name.tld