If it's just one picture. Attach it to an email and save it in drafts. Pick it up off your email account on the computer... If I can't be bothered to sync my phone for a new picture I've taken, that's what I do. Arse about face, but quick!
Can't you just Browse Device in the Bluetooth menu on the Mac? Or click on the device and Browse? That's what I do with my Phones. Nokia, Motorola. Is the iPhone different?
Flickr app. Upload one pic, a batch of pics or just take a photo within the app and upload it. Then lots of options for downloading those pics back to your PC.