Images used in this tutorial are by Daniel Bell.
Sometimes, when you drag one image into another it's really quite obvious that the tree, person or whatever you dragged over isn't meant to be there. But this problem can be easily rectified by simply adding a shadow in Photoshop.
First you need your two images - we're using a shot of a desk and a candle in a bottle which at the end will sit at the front of the desk.
Step 1: Remove your background
If you drag the image you want to appear on your new background straight across you'll take everything not just the object so it needs to be cut out of the background. The quickest way to do this is with the quick selection tool. Simply draw around the object until it's all selected then go to Select>Inverse to select everything but the object. Make sure your layer isn't locked then to cut it out go to Edit>Cut and the background will vanish leaving, in our case, just the bottle. Go to Select>Deselect and if you need to tidy your selection up use the Erase Tool to remove any bits you don't want to be included in your selection.
Step 2: Drag your object into the new background
Use the Move Tool to drag your object onto the new background. Our bottle is far too big to sit on the table so we need to resize it. To do this go to Edit>Free Transform and drag one of the corner anchor points in until your object is the right size. If you hold shift your object won't get distorted when you resize it. Hit the enter key on the keyboard when you're happy with the size.
Step 3: Look at shadows
Your object's now in place but it's obvious it's pasted in. To combat this we need to give the object a shadow. Before you start take a look at the shadows of objects already in the shot so you know what direction you need your shadow to be.
Step 4: Duplicate your object layer
Duplicate the object layer by dragging it to the layer icon in the layer palette or click it and select Layer>Duplicate Layer from the menu. With the duplicated layer active go to Image>Adjustments>Threshold. This will open a histogram with one slider. Drag it all the way to the right and you'll notice all the selection becomes black. Click OK and you now have a shadow of the object covering the layer below.
Step 5: Move your shadow
Go to Edit>Free Transform and move your cursor just off from one of the corner anchor points to give you an arrow that's curved with two arrow heads. This will let you rotate your selection as well as drag it into place. Play around until the shadow looks natural.
Step 6: Reduce the opacity of the shadow
It doesn't look much like a shadow currently so go to Filter>Blur>Gaussian Blur and adjust the radius slider so the shadow softens. Make sure Preview is selected so you can see the result as it changes on the actual photograph. After doing this you may need to use the Move Tool to readjust the position of the shadow again as it sometimes moves. If the shadow is still a little harsh reduce the opacity of the layer. Around 70% should be fine. When you're satisfied with the result save it.
Whether you're a beginner looking for a compact camera or a pro in the market for a high-end DSLR visit Nikon – the company who has photographic gear to suit everyone.