iTunes has changed since the original thread back in 2012. Image Capture is much better. You find that in the Applications folder. Connect your iPhone by cable to the Mac, open Image Capture and in the left column you will see all devices that IC can capture images from (My all in one printer is there, for example, because Image Capture can capture scans). Select your iPhone and in the large window all the images on the phone will appear. It may take a while for the images to be processed and you will need to unlock the iPhone if it has a security code set. Once the images start to show they should be in a long list with a thumbnail of the image. To change to all thumbnails, there is a little icon on the bottom of the window with four squares. Click that and thumbnails in a grid will appear. Beside that is a set of four horizontal lines to click if you want the list back. At the bottom of the window is a box labeled "Import to:" and beside it the default for where these pictures will go. Use the up/down carets to select where you want the images to be saved on the Mac, then click each image you want to import. If you want to import all, you can click "Select All" in the Edit dropdown on the top bar of the screen, or you can click on the first one you want, scroll to the last one, hold Shift and click on the last and all between will be selected. The selected ones will be highlighted in Blue on the list or with a grey surround in the grid view. Once you have them deleted, click the "Import" box on the lower right. If you just want all of them, you can skip the highlighting and click "Import All" and everything will be brought over. It can take some time, so let it run. You can use Finder to go to the location you are importing them into and watch them arrive, if you want. I generally just go get a cup of tea.
As I said, iTunes has been changed, and I think it no longer handles images. I really don't know because I quit using it when Apple removed support for apps from iTunes.