You may change the size of a specific layer in Photoshop.
In oder to do so, simply follow the following steps:
• In Photoshop, click on the layer you wish to resize in the Layer Panel
• Go to the Edit tab
• Go down the list to Transform and then to Scale
• This will trigger a resizing frame around the element in that specific layer
• You will now be able to resize the layer
• Note that there’s a short cut for this. On a Mac, this Command T and on a PC this is Control T