One easy method of combining two pictures into a single image is to use the bundled graphics and painting application of a computer's operating system. Simply copy and paste each picture into one new image file, then save that file to create a new picture with both images in it.
First, open each picture to be combined in a separate application window. Resize each image so that they have identical dimensions, which makes pasting the pictures together easier. This can usually be accomplished in the Properties setting of each image.
After the images are resized, save them and then open a new image file. Adjust the size of the new image file so that it is exactly the size of the two images to be combined. Copy one of the pictures within the application with the Select All and Copy commands, then use the Paste command in the new image file to insert it into that new file. Repeat the previous step with the second image, moving the second picture around in the new image file until satisfied. Finally, save the new image file. The two pictures are combined into one.
Each operating system has a native graphic editing and painting application; for example, Microsoft Windows has Paint and various Linux operating system distributions have KolourPaint, Pinta or XPaint. All of these applications have essentially the same functionality.