[MRG] Update examples in the doc

[rflamary]

Types of changes

In this PR we are upadting the exmaples inthe doc to make them more interpretable.

List of stuff TODO:

• Move Screenkhorn to section "other"
• Update logo with transparent version

Motivation and context / Related issue

How has this been tested (if it applies)

PR checklist

• I have read the CONTRIBUTING document.
• The documentation is up-to-date with the changes I made (check build artifacts).
• All tests passed, and additional code has been covered with new tests.
• I have added the PR and Issue fix to the RELEASES.md file.

[codecov]

Codecov Report

Merging #359 (ed052c5) into master (0afd84d) will decrease coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #359      +/-   ##
==========================================
- Coverage   93.78%   93.75%   -0.04%     
==========================================
  Files          23       23              
  Lines        5845     5845              
==========================================
- Hits         5482     5480       -2     
- Misses        363      365       +2