Open file "Metal Ball". Select the Elliptical Marquee Tool and make a selection of the ball. Hold shift while dragging to keep the selection a perfect circle. After you've selected the ball press Ctrl + C to copy and Ctrl + N to create a new document. Photoshop it's smart enough to calculate the dimensions of the selection and input those variables into document creation window so all you have to do it's to press Ok. Paste the image (Ctrl + V).
Now we have the ball selected into a new document and the reason for this it is that the door in the middle of the ball kind of ruins the whole aspect of it. We need a nice, round metallic ball and this is the only decent image of a chrome ball I could find, except it has an ugly entrance of some sort that's ruining its symmetry. Notice that the door it's mainly in the right half of the image while the left half looks good. The solution to this it is to use the good half to correct the bad one. This technique I am about to use it's useful when you are retouching or correcting symmetrical objects and it also works great on human faces.
Let's begin by selecting the Rectangular Marquee Tool and make a selection of the left half of the ball.
Click on the ball layer to select it and press Ctrl + J to copy the selection on a new layer. I turned of the visibility of the ball layer temporarily so you can see the half ball layer.
While on the half ball layer press Ctrl + T to enter Free Transform. Right-click and choose Flip Horizontally. Hold Shift and drag the half ball to the right to position over the original right half.
Add a layer mask to the half ball layer (Layer > Layer Mask > Reveal All) and Alt-click between the half ball and the original ball layer in the Layer palette to clip the upper half ball layer to the lower original ball layer. This means that the half ball layer will be visible only through visible pixels below, so if you did not placed the half of the ball exactly over the right half of the ball in step 4 you don't need to worry about it now.
Selecta soft round Brush Tool at a decent size (100px) an paint with black in the layer mask to hide the areas encircled below.
To get rid of the ugly black spot in the middle and to make the ground look right we will repeat the trick from step 2. Let's make a selection of some ground that looks good on the right side and make press Ctrl + C to make a copy of selected area (before you press Ctrl + C turn off the visibility of the white Background layer an make sure that you have selected the ball layer in the Layer palette). Create a new layer on top of all layers (Layer > New > Layer) and press Ctrl + V to paste it.
Now it is only a matter of placing this layer on the right side and using Free Transform and warp to make it fit. Add a layer mask to this layer (Layer > Layer Mask > Reveal All) and using a round soft black brush tool paint over the obvious edges. You should have something like the image below.