Transfer Wallpaper To iPhone?

I want a new wallpaper for my iPhone.
The old one is kind of lame and outdated, I would've changed the wallpaper before but I don't know how to do it.
I would like to change it for a picture I have in my computer of my cat, how can I transfer the picture to my iPhone?

The wallpaper is one of the most important things on my iPhone. It is the main background image you will see every time you look at your iPhone so it is best to pick one of your favorite pictures.
It is easy to change the wallpaper on your iPhone as often as you like.

1. Find the image of your cat in your computer. Move it to your "My Pictures" folder or iPhoto library on a PC or Apple respectively, or wherever you prefer to store your images on your computer as long as you will be able to easily locate it.

2. Connect the iPhone to your computer with the USB cable and wait for iTunes to launch itself automatically. Click on the "Photos" tab in the side panel.

3. Click on the "Sync Photos From:" tab in the "Photos" menu on iTunes and locate the folder where your photos are stored. Select all of the images that you would like to transfer your to iPhone, keeping in mind that you will assign the photos as wallpaper to accompany specific menus or contacts later. Click on "Sync" in iTunes to transfer all of the photos to your iPhone.

4. View the photos transferred from your computer to the iPhone to decide which to use as wallpaper by tapping on the "Photos" icon on the home screen. You can zoom in on any photo by pinching your fingers together and moving them together or apart. You can also zoom in and out by quickly tapping twice in a row and then repeating this motion again to zoom in the opposite direction.

5. Change the primary wallpaper on your iPhone by tapping on the "Wallpaper" icon in the "Settings" menu. You will then see a menu displaying thumbnails of all of the photos stored in your iPhone. Choose a photo by tapping the "Options" button and then tapping "Use as Wallpaper."

6. Adjust the appearance of your wallpaper photo by dragging the photo around the screen until only the portion you would like to use is visible. Zoom in or out to adjust the size of the image you plan to use as your wallpaper. Finish by tapping "Set Wallpaper" to save your adjustments.

You can also use the iPhone's built-in camera to take a picture to use as wallpaper. Tap on the "Camera" icon and then simply point the iPhone's lens, located on the back of the iPhone, and tap again to take the picture.

See? It's easy and once you learn the steps, you'll do it in no time.

You can't download any wallpapers directly off the internet from the phone itself unfortunately. What you should do is make a folder in your Pictures folder on your computer and save all the wallpapers from whatever site in that folder.

Then follow the steps above and you'll be able to set any picture you want as your wallpaper.