Hello if you right click on a movie and choose "Re-Update Automatically" action, the script downloads all data and overwrights previous data, but it downloads the cover/poster AGAIN, so now there are two SAME posters in the cover manager.
It's because covers can't be overwritten because you might have loaded the existing cover(s) from another site. There is no check if two covers are identical, therefor they are always added. I think this can't be changed.
In order to achieve what is possible, you have to try the impossible over and over again. Hermann Hesse
With the new IrfanView version the compression changed for jpgs and therefor the resulting jpg's are different. Different file-sizes and content = XMM can't detect that the images are the same.