is it possible to upload photos on an iphone to a computer via a cable rather than accross wifi?
Yes. The Dropbox desktop app has the Camera Uploads feature as well.
Thanks but as soon as i turn the wifi off the Camera Uploads message says waiting for wifi?
You don't do it through the mobile app. You do it through the Dropbox app installed on your computer. Follow the instructions in the link I provided above. Also, make sure you have the necessary drivers for the iPhone installed so your computer can see the iPhone as a drive.
Thanks - I can see my iphone under my computer(PC), but dont have a preferences option- in settings or elsewhere and cannot find the button to turn uploads on/off anywhere