Do you know how can I change the cover for a manga with a picture of best quality. It's for a titles that I created, at this moment I didn't find a good picture. Thanks for your answer, sorry if you already gave the explanation.
@fati You should see the light blue Edit button on the same line as Actions.
That enables to edit all manga informations and upload covers as well.
If you don't see it you don't have contributor/editor rank but you could ask for it.