Images linked with raw=true don't render

[KarthikNayak]

Expected Behavior

So when images are linked via markdown and the link ends with ?raw=true they fail to render.
Often this is added to refer to relative paths in Github: https://stackoverflow.com/questions/10189356/how-to-add-screenshot-to-readmes-in-github-repository

Actual Behavior

Images with the following syntax ![Alt text](./relative/path/to/img.jpg?raw=true "Optional Title") don't render.

Steps to Reproduce

1. Add an image ./relative/path/to/img.jpg
2. Create markdown a.md with ![Alt text](./relative/path/to/img.jpg?raw=true "Optional Title")

Software Versions

• Markdown Mode: 20200622.20
• Emacs: 26.3
• OS: Linux

[syohex]

I have merged #513. Please check latest version.