No... due to the concerns raised by a number of people, we will not be visually altering the images in any way.
It may be the case that we incorporate a system whereby you can 'opt-in' to some sort of watermarking when you upload a gallery... but this will need to go on the 'todo' list for the site.
In the meantime, there are a number of pieces of software around which should be able to do this for you automatically before you upload the images.