Apple is known for being especially user friendly. Unfortunately, needing to use iTunes for copying pictures from a Windows PC or Mac to an iPhone is not one of the most intuitive aspects of Apple's smartphone.
As a result, many users today are turning to alternative solutions, transferring photos between devices through email, cloud-based services like DropBox , Apple's own iCloud, AnyTrans, Simple Transfer, or Apple's Mac-only Airdrop.
Although still supporting iTunes for photo syncing, Apple now puts a lot of emphasis on the iCloud Photo Library as a place for users to store pictures and transfer images between devices. After all, iTunes is actually mostly an online marketplace for selling content to users.
However, the time-honored method of using iTunes for photo transfer is really not very hard, as long as you know what to do. Here's a 10-step process for moving images from your computer to your iPhone.
Back up all the photos already in the iPhone to your computer to prevent them from getting overwritten. Do this as you would with any digital camera. Plug the iPhone to the computer and open iPhoto, or whichever photo software you use, to import the photos.
Sort the photos on your PC and Mac. Unless you want to move all photos or just favorites, select the pictures that you want to move to the iPhone and place them in in a specific folder or subfolder.
Connect the iPhone to your computer, if not connected already, and launch iTunes on the PC or Mac.
Click on the iPhone icon on the left sidebar of the iTunes window. This will open the summary page for your device.
Select "Manually manage music and videos" if it's not already selected.
Click on the "Photos" tab and select "Sync photos." If instead you see "iCloud Photos is On," all of your photos and videos are already on all of your devices that use iCloud Photo Library. So syncing them through iTunes isn't necessary if you want to access them on your iPhone through iCloud.
Choose to sync all photos, selected albums, or favorites only. You can also choose to sync videos, if you want.
Click the "Apply" button in the lower right-hand corner of the window to begin the sync process.
When the sync is complete, eject your iPhone and view the photos by tapping the "Photos" button on the home screen.
Plug your iPhone back in to your PC and uncheck "Sync photos from" to delete photos stored on the device. You can turn off syncing from just one of your folders or all of them at once.