[SOLVED] Moved site to different host but image URLs still point to the old one

I am helping a friend to set up her website. We developed it on my host's server, and then moved it to hers (never again!). I thought I followed the codex instructions carefully, and everything seemed to be all right, but now we've discovered that the image urls are all still pointing back to the old server. Is there anything I can do to change this in one go rather than having to edit every image?

Thanks
Graham