I use the following markdown for images in Obsidian, which all work:
Foto1:
<img src="file:///P:/Obsidian/BBZ/Schulisches/KuK/attachments/NN.png"></img>
Foto2:
<img width="80px" src="file:///P:/Obsidian/BBZ/Schulisches/KuK/attachments/NN.png"></img>
Foto3:
![[../../../../../BBZ/Schulisches/KuK/attachments/NN.png]]
Foto4: (geht **manchmal** nicht!)
![[NN.png]]
Foto5:
![[BBZ/Schulisches/KuK/attachments/NN.png]]
These markdown codes give me results:
Foto6:
![[BBZ/Schulisches/KuK/attachments/NN.png|100]]
Foto7:
[[NN.png]]
Foto8:

Foto9:
[[NN.png|100]]
Foto10:

Are there any other possibilities with markdown to view images?