Using Layers and the Fuzzy Selection Tool in GIMP we will make a composite image like the one above.
Step One
Copy and Paste the Butterfly image into the baby picture.
Open the Butterfly image
Hit CTRL - A (select all)
Hit CTRL C (copy)
Go to the Baby image and paste the butterfly. This will create a new layer.
Step Two
Orient the butterfly using Move Tool
Hit the M key or click the Tool circled to the right.
Select the Butterfly Layer
Drag the Butterfly where desired.
Note: Now you will notice that the picture is not perfect. The background of the Butterfly image copies along with the butterfly itself. The next step will allow you to select and cut the background of the butterfly out but keep the butterfly.