Good afternoon. My website, a free classified ads site, is hosted by XO, the hosting company. I'm introducing a feature where advertisers can, for free, post pictures of the things that they're advertising -- that is, where advertisers can upload a JPEG or a GIF. I understand that this can open my site up to the uploading of malicious code, and that I should put safeguards in place to make sure that only JPEGs and GIFs get uploaded. However, I'm wondering if XO doesn't include some built-in safeguards that would keep malicious code from getting executed. In other words, since a profesional hosting company runs the servers -- not me -- do I need to be worried about security at all?