@ricardoclaus If you are using Recalbox 6.0, do not use the internal scrapper, it is not working, it is a known bug.
Use an external Scrapper, I recommend the ARRM:
But you can use any other you want:
Regardless of which Scrapper to use, the name of the image and the name of the folder it is in does not matter, SINCE IT IS CORRECTLY IN GAMELIST. If there is -image at the end of the name it does not matter, whether it's in the downloaded_images folder or the media folder, whatever, IF GAMELIST IS EQUAL.