Moving some folder with images into Uploads folder

I’ve got some folders in the root of my blog (http://www.davidesalerno.net), and these folders there are all the images/attachments which I’ve uploaded in 3 years of blogging.

I want to move these folders such as http://www.davidesalerno.net/immagini or http://www.davidesalerno.net/foto into default uploads folder into wp-content folder because it’s more tidy.

I made a copy of these 2 folder so the same files that there are in http://www.davidesalerno.net/immagini there are into http://www.davidesalerno.net/wp-content/uploads/immagini too. I replaced all the references to the old file locations in the database to the new locations.

So for exmple if before there was in the database the reference to
/home/username/davidesalerno.net/immagini/images.jpg
now there is the new location
/home/username/davidesalerno.net/wp-content/uploads/immagini/images.jpg

Everything works fine because images are loaded correctly evenif when there should be loaded images in thumbnail or medium size something breaks and it’s loaded the image in full size (in the img tag the url is to the full image and not to the resized one).

What should I do to make all works correctly?
Thanks a lot for help,
Davide