[Smush Pro] Bad Image qualitiy in our WordPress Account since activated Smush PRO

Hello,
we have big problems with the quality of our images, since we buy and aktivated Smush PRO last week. We deaktivated Smush PRO to see if it will be better, but it isn’s. The problems are the same. Now we see, that the quality of our images is online bad an also in our wordpress accout. Why are the images bad in our WordPress Account?
Our Website is https://pauschalreisecheck.de

We hope you can help very fast. Our E-Mail-Adresse: info@pauschalreisecheck.de

Thanks and best regards.
Stefan