(This is a recreated bug report, since the problem still persists.)
Steps to reproduce
Have a picture called example.jpg in the root of the vault.
Have a note in the root of the vault - test.md with the following content:

Create a folder called foo. Move the picture from the root to foo and let obsidian update the links.
Expected result
The content of test.md is as follows:

Actual result
The content of test.md is as follows:

Environment
- Operating system: mac OS 10.15.6 Catalina
Additional information
1Writer for iOS tends to create images links like this and the text in the square brackets is also used by some markdown software as alt text.
File->New Link Format is set to Relative Path.