I solved the problem...and came to a decision
Hi, in regards to my post from the weekend:
https://www.reddit.com/r/ereader/s/NJSQJq9gpB
I managed to solve it. It seems that there are some compatibility issues with epub files and pocketbook, resulting in the fragmented pictures shown in my previous post. After I converted the file from Epub into PDF it worked perfectly fine. I also discovered that other Epubs from the same Manga series, that previously worked fine, now show the same problems. I suspect that the problems started with the last firmware update for the Pocketbook Inkpad Color 3, but am not sure, as this is the first time in almost a year, since I last used it to read a Manga, so the problem might be present for even longer.
I'm happy that I managed to solve the problem and found a solution, that (hopefully) will always work, but it joins a series of annoying problems I have with pocketbook. Even though it is a open system that claims to support tons of diffrent kinds of EBooks, there always seems to be a catch, that involves, at least for me, the usage of third party software to solve, resulting in a user experience that is quiet far away from a simple download on the Pocketbook or a drag and drop via your PC, like I imagined/ Pocketbook tries to paint. Combined with the very slow browser that can't access many online shops because it is to slow for the captcha tests on those sides and the unsatisfying selection in the Pocketbook store, at least here in Germany, I think that my next Ereader will not be a Pocketbook. Instead I'm going to buy a Tolino or Kindle as they are simpler and better to use and therefore better for my average needs that do not exceed anything that I can not buy in the shops of saied companys.
Of course those are just my personal experiences and other people could have diffrent experinces and opinions.
However, thanks to all the people that helped me with their ideas and tips^^