This tutorial will show you how to copy an image and paste it into a selection within another image using the Paste Into command in Adobe Photoshop. The article will also show you how to fix any perspective problems between two images using Photoshop's Free Transform command.
Step 1: Select an area to paste the image into
The example will select an area inside the TV so that the second image can be pasted there. Since the screen is just a polygon with straight edges, it can be selected using Photoshop's Polygonal Lasso Tool.
On the toolbar, click and hold the standard Lasso Tool to reveal other tools hidden behind it. Then, select the Polygonal Lasso Tool from the menu.

How to draw a selection with the Polygonal Lasso Tool
To use the Polygonal Lasso Tool, simply click around the area you want to select to add points. Photoshop will then connect the points with a straight line. So the idea is to click on the points where the line needs to change direction. The example image will be the 4 corners of the screen.
Click the upper left corner of the screen to add a starting point to the selection. Then, moving clockwise, click the upper right corner to add a second point. Add a third point in the lower right corner, then add a fourth point in the lower left corner.
Don't click and drag with the Polygonal Lasso Tool. Just click to add points then release the mouse button. And if you accidentally click on the wrong point, press the Backspace key on a PC or the Delete key on a Mac to undo the last point.

To complete the selection, click the starting point again. In the case of the example, that point is in the upper left corner.

The selection border appears and is ready to paste the image inside.

Step 2: Open the image to paste into the selection
Once the selection is selected, open the image you want to paste. Switch to the second image by clicking the Document tab at the top.

Step 3: Select and copy the image
Select the image by going to the menu Select in the menu bar and select All. A selection border will appear around the image.

Switch back to your first image (the one with the selection) by clicking its tab.

Step 5: Paste the image into the selection
Then, to paste the copied image into the selection, go to the menu Editselect Paste Special Already Paste Into.

Photoshop converts the selection into a layer mask
Note that after pasting the image into the selection, the selection border has disappeared. That's because Photoshop has converted the selection into a layer mask.
In the table Layerswe see the mask in the layer mask thumbnail. The white part of the mask is the area we have selected and is where the image on the layer displays. And the black part is the area outside the selection and where the image is hidden.

If you hold down the key Shift on your keyboard and click on the layer mask thumbnail, you will temporarily turn off the mask.

When the mask is off, the entire image is visible.

Click the layer mask thumbnail again to turn the mask back on and display the image only in the area you selected.

Step 6: Resize the image inside the selected area
Also, notice in the Layers panel that the area between the image thumbnail and the mask thumbnail is blank, meaning the link icon is not visible.
Typically, the image and its layer mask are linked, meaning it is not possible to resize one without resizing the other. But when pasting an image into the selection, the image and mask are not linked, so we can resize the image without affecting the mask.

Make sure the image is active, not the layer mask, by clicking on the image thumbnail.

Then go to the menu Edit and choose Free Transform.

To resize the image, click and drag the handles. In a moment, we'll show you how to fix any perspective problems with your images. But for now, the article will only focus on width by dragging the side handles into the sides of the TV.

Step 7: Adjust the perspective of the image
Because the image is straight but the TV is tilted, we have a perspective problem. So to adjust perspective, right click inside the Transform box and select Perspective.

In Perspective mode, dragging a corner handle horizontally or vertically will move the handle in the opposite corner along with it but in the opposite direction.
So drag a corner handle up or down until the corners of both images are aligned. For example, we will drag the top right corner handle up.

Fine-tune perspective using Distort mode
Sometimes Perspective mode is all you need to align the top and bottom corners together. Other times, you can't align one corner without skewing the other.
Note that the top corner is now correct but the bottom corner is not.

To fix that, right-click inside the Transform box and switch from Perspective to Distort mode.

In Distort mode, each corner handle can move independently. Therefore, you can drag the bottom right corner handle up to align the bottom corners without affecting the top corner.
If you hold down the Shift key on your keyboard while dragging, you limit the direction you can move, making it easier to drag straight up or down.

Switch back to Free Transform mode
The author wanted the basketball player to take up more space on the screen. But before the image can be resized again, it's necessary to right-click inside the Transform box and switch from Distort or Perspective mode back to Free Transform.

Then, drag the corner handles outward to resize the image.

Reposition the image
You can also drag inside the Transform box to reposition the image and center the subject.

Fix any new perspective issues
If resizing the image causes the perspective to be lost again, right-click inside the Transform box and switch back to Distort mode.

Then drag any corner handles as needed.

Step 8: Close Free Transform
To accept and close Free Transform, click the check mark in the Options bar.

After resizing the image, centering the object on the screen, and fixing the remaining perspective issues, here is the final result.
