All pictures were found by using https://search.creativecommons.org/. They are marked for free, unlicensed usage and have a creative common license.
The authors of the pictures are in no connection to TopSoftDE.
The author's names are mentioned on this page and not in the app because there is not enough space for these long names. In the apps there is a link to this website so user will know where to find the authors of the pictures. If your picture is used and you want us to remove it from this website and our apps although you have marked it for free and unlicensed usage, contact us. We will remove it as soon as possible.
The following document includes the same information as the downloadable document from the top. The downloadable one is much more clearly to understand. Use this if the download does not work.