The About page style is broken.

[godsman-yang]

baseurl: / url: https://{username}.github.io/

The about page style is broken because that page tries to find images from about/assets/images. The Images related to about are located in the assets/images folder.

[Jetroid]

{{ site.baseurl }} is entirely unnecessary in a user site (ie one where jasper2 can be found at https://{username}.github.io/ )

I suggest doing this:

in _config.yml, set:

baseurl: ""

then run this script:

find /path/to/jasper2/ -type f -exec sed -i 's/{{ site.baseurl }}/\//g' {} \;

... which replaces all instances of {{ site.baseurl }} with /, so links are relative links.