SVG images do not show up

This is a problem caused by mime-type. It occurs for the same reason as #292.

## SVG images do not show up

![image](https://user-images.githubusercontent.com/5798442/119813087-d435fa80-bf23-11eb-9a54-6a2d5b1e3aef.png)


## Exepected behavior
![image](https://user-images.githubusercontent.com/5798442/119812769-77d2db00-bf23-11eb-9da7-ea6567136cbe.png)