To transfer iPhone photos that are stored on your computer, you need the program iTunes. It was developed by Apple and designed to transfer files from computer to iPhone and Vice versa. You can download it on the official website at
After installing iTunes on your computer, run the program and connect your iPhone using USB cable. Click on the left menu on the iPhone icon under "Devices" and navigate to the main window on the tab "Photos".
Here you need to specify the path to the folder containing the pictures you wish to transfer to your iPhone. To do this, click on the button "Sync photos from" and select the desired folder on the hard disk of the computer. Click "Sync" in the lower right corner of the program window, and pictures will be transferred to the iPhone.
If you need to upload to your iPhone pictures from the Internet, this is done without the aid of a computer. Open your Safari browser and navigate to the site from which you would like to upload images. After you open the page, touch the screen area of the picture and hold your finger for a few seconds.
On the screen a menu will appear in which you need to select the "Save image". After that, iPhone will download pictures to my photo gallery. It was there and be late for all these uploaded image.
Another option to download images in iPhone using special apps from AppStore. Download one of the free apps to find your photos on the Internet (for example, iWallpapers or Flickr), and then select any image and save them from the menu.
To do this, in most applications, simply at the bottom of the screen on the icon arrow, and then in the menu that appears, choose save the picture.