Bug when adding a podcast image that already exists.

When creating a podcast,

if the file (media/' . $podcast_name.'/'.'cover.' . $image->getExtension()) already exists,

then it creates (media/' . $podcast_name.'/'.'cover_1.' . $image->getExtension()) (_1 is added)

but (media/' . $podcast_name.'/'.'cover.' . $image->getExtension()) is stored in the database (so the old image is visible instead of the new one).