With at least 1 out of 5 companies using social networking sites in the hiring process, people have been smarter about deleting pictures before going to job interviews. But it turns out, the website it’s self may not be doing the same.

Researchers posted photos on 16 social networking and Web 2.0 websites, keeping a careful record of the URL associated with the photos, before deleting the images. Even after this supposed deletion the researchers were able to find the photos on seven of the 16 websites a month later, simply by visiting the web location associated with the image.

The problem arises because sites often fail to remove image files from their photo servers after they are deleted from the main website.

Photo-sharing sites such as Flickr and Google’s Picasa, as well as Microsoft’s Windows Live Spaces, removed content from its servers upon deletion. But photos posted on sites including Facebook lingered in caches, even after images were removed from a user’s profile. Other offenders include MySpace and Bebo.

Which honestly if a new employer is searching for stuff you should be safe. But the email sent to HR about your weekend, well the link to those pictures is still probably going to work. Remember if it was on the Internet, chances are you can’t get rid of it, so make sure it is really really good.

(Via The Register, Research by Light Blue Touchpaper)