Check pictures in for impementers' guide post

[chrbertsch]

@filip-jezek : Could you please check if the fmi and prostep logos are displayed correctly in https://github.com/modelica/newsletter/blob/main/_2023-01/fmi3-ig-published.md?
In the preview they do not get displayed. Is this due to the svg format? Thanks!

[filip-jezek]

The final rendering is somewhat different from the one at preview. You can however always check at https://newsletter.modelica.org/2023-01/index , it takes just some time to update though. So it is not due to cvg, but I haven't been able to resolve why the FMI logo does not show up and just the prostep shows. Maybe because they are both right? You can check the html source code, it is there, it just does not show up.