Options: (1). Click on the locked layer in the " layers " palette. This is the long box on the right of your screen labeled layers. (2). Select layer alpha and then resize the image. To prevent the color from melting and taking up so much of the background layer, select the layer alpha layer separately and resize it till it matches. (3). Make sure that when you open it, it appears in its original state (i.e. dashed, down-centered, uncurved). (4). Make sure the layer you created is right. If it is, your selected layer should have replaced the previous layer.Choose from options above and answer: What most naturally follows?

How to unlock layers in photoshop
Open up your image in photoshop like normal.
There is no sort of change or setting you can switch before opening an image that unlocks the background layer. Just open up the image like normal.
Answer:
(1).