Hi Dragon, cant thank you enough for helping me out. I think I found the illusive issue !!!
After trying the core change which worked, but didnt solve the bezels, I noticed in your screenshot you dont had EXTRACT ROMs checked and all my SNES roms are zipped (and tagged to extract).
Then I unziped one and saw that the name of the rom was not matching exactly the zipped name (the zipped one match the cfg files and bezel names), it had some V1- at the end.
Once I renamed the file to the same name, bezels came working without having to do any configuration anywhere. All the time, the zipped corrected names were masking the wrong names of all roms inside, for this SNES pack I have, all seem to have something at the end. Then I checked my NES roms, they all match the .zip and .cfg files, thats why they were working.
Do you know if when importing roms in Launchbox, do they need to have the "standard database name" or does launchbox does a translation of the "detected variant" file name and for the cfg, media and bezels to match the same name ? I was thinking if I delete all SNES roms I have, then delete all cfg and bezels and then import again with the new naming, will it download and recreate the files to make it work ? or is just better to find a new rom set that have the right naming ? Thank you !