Hi5 has implemented a technique to avoid saving of pictures from someone’s (including yours) profile. The trick is done by adding a layer above the photo called 1x1_trans.gif and when you try to save a photo, you get the same file saved, not the photo you want to.
I faced a similar scenario when I recently tried to save my own pic. So what I did was just adblocked the image (yes I use Firefox with Ad-Block plus) and after that, 1x1_trans.gif was blocked by Ad-block Plus and I could easily save my photos.
In layman’s terms, assuming you have neither Firefox or Adblock installed, install firefox from http://www.mozilla.com and then Tools > Add-ons and search for Adblock Plus. You must restart Firefox after installation is complete. Then open hi5 and then right click on any image to be saved and then select Adblock Option. Then confirm it. Then just save any photos as normal.
I’m sure there are several other ways to achieve the same, but that was the easiest for me.