You can store additionnal files related to the yaml file.  
As exemple, with _index.yaml, you can add _index.01.md or _index.01.svg.  
You can use the same method with item.yaml files.  
Thoses files can be added as headfile, file or footfiles just using 01.md or 01.svg.  

### Supported extentions
Text: txt adoc  
Parsed: md html pug  
Images: svg png jpg jpeg gif bmp