You can change the background of a photo or creatively combine two images by superimposing one over the other using the free photo editor at Pixlr.com. To do so, you must remove the background of the image you want to superimpose, making it partially transparent. Then you can combine the two photos by pasting the transparent one onto the unedited picture. You can superimpose multiple photos as well, creating separate layers to place images in front of or behind each other.

Prepare the First Photo

Step 1

Select "Pixlr Editor" from the Pixlr home page (see Resources) and click "Open Image from Computer." Navigate to the image you want to superimpose onto another and open it.

Step 2

Double-click the "Lock" icon on the thumbnail of the image in the right side of the screen. This enables you to make the background transparent when you erase it.

Step 3

Click the "Eraser" tool from the toolbox on the left. Choose the brush style and size using the options in the toolbar just above the photo.

Step 4

Press and hold the mouse button while dragging it on the areas of the photo you want to erase. Change the size of the eraser as needed to erase smaller sections.

Step 5

Select the "File" menu and click "Save." Enter a name for the file and choose "PNG (Transparent, Full Quality)" in the Format box. Choose a location and save the file. Close the image.

Combine the Images

Step 1

Select the "File" menu, click "Open Image" and open the photo onto which you want to superimpose the first picture.

Step 2

Select the "Layer" menu and choose "Open Image as Layer." Select and open the photo with the transparent background.

Step 3

Click the "Move" tool and drag the superimposed image where you want to place it.

Step 4

Resize the superimposed image by selecting the "Edit" menu and choosing "Free Transform." Grab a corner or side of the image and drag it to the size you want.

Step 5

Press "Ctrl-S" or select the "File" menu and choose "Save" to save the combined photos as a new image file.