Note these are instructions for a windows pc
Wirelessly (Note:this method only works if you have cloud photo stream set up on your iPhone setup)
To set up iCloud backup go to settings and click I cloud then click all or some of this things it allows you to backup turn them on and then scroll down and click iCloud backup it will take you to a new page where you turn backup on and you can now back up over wifi instead of your computer ( to back up you need a iCloud account to set up just follow the onscreen instructions and login with your AppStore email and password and it will create the account)
Here is how you do it download or use apple software update included with your install of iTunes and look for a download when apple software update does a check for updates called iCloud utility manager download and install
You can find it once installed under control panel all you have to do is click on the search bar and type iCloud click on the only search result it will open sign in with your iCloud I'd and turn on photo stream and you photos will download to your computer. They will be under your user photos or it will be named picture under a folder called photo stream should take 5-10 min to download photos depending on how many you have
Connect your data and sync cable between your computer and iPhone then wait for the driver software to install if you have already done this open my computer or your main system drive on your computer and click on iPhone or what ever you named your device it should be identified by default as a digital camera click on it open the folder inside it (note the folders name has numbers and letters) then presto their are your photos just highlight and copy them to you computer and now you have a backup or separate copy of your photos.
One little recomendation the iCloud setup takes a while but is a time saver in the end just a word to the wise.