Dear friends, this livery might be installed without using Livery Manager. Just unzip the folder with livery and put it to folder with plane. There is a read me file in archive, you can find everything you need for installing in that read_me file.
I found the way to fix it. After uploading and saving your file just edit it/ I mean just upload screenshot again and it'll be much more better quality
I figured it out a month ago. Still, too bad it isn't fixed yet.