Foreword

I filed sbarex/QLMarkdown/issues/80 and it's author informed me that they use your cmark-gfm as their Markdown parser.

Feature request to the cmark-gfm parser

Allow whitespace in filepaths inside the round brackets while:

• fully compliant syntax experiences no misinterpretations from this more relaxed interpretation,
• performance impact remains negligible.

At least the whitespace. If possible be as easy and relaxed as possible:

• Everything inside the round brackets is considered being the filepath.
• Only round brackets themselves need escaping of course.
• Whitespace and other special characters get handled/escaped by the system automatically (specific to the filesystem — NTFS, APFS, EXT, … — or transport scheme — file/http/https — where it is in use)
• If it does not start with a slash it is considered a relative path.

Design Rationale

• Markdown's goal was/is an easily human readable and writeable markup language!
  • Having to change filenames prior usage with Markdown
    OR
  • Having to transform each   to %20 in the filename everywhere
• … contradicts both goals IMHO!

Best Practises

• Macdown which uses hoedown supports this.

Sample

## Images
### Filename without whitespace
![](1.png) --> Render the image inline.
### Filename with whitespace
![](1 b.png) --> Shows the raw markup language instead or rendering the image.