## Summary of Changes
This is a pull request where we can make incrementally improvements if
it means to change figures.
The first milestone is that the Package Overview page looks good.
The first commit makes the background of the 3D Convex Hull teaser
transparent.
## Release Management
* Affected package(s): All
* Issue(s) solved (if any): fix#9422
* Link to compiled documentation (obligatory for small feature) [*wrong
link name to be changed*](httpssss://wrong_URL_to_be_changed/Manual/Pkg)
* License and copyright ownership: unchanged
Sebastien Loriot
9498c7213a