Resizing an image in gimp

1. Select the Layer you want to scale. In your Layer selection dialog.
2. In the menu bar of the main window select Layer or press Alt+L
3. Go down to Scale Layer... or press S
4. Happy scaling

Hope this is what you wanted.

you will be better off with photoshop. Gimp is extremely limited, you will have a hard time resizing layers, however if you insist then go to Tools -> Transformation Tools -> Handle Transform.

Left Click to add and move handles Ctrl+ Left Click to remove handles. just be careful if Gimp adds to many handles (any more than 2) as it can make it difficult to get your layer in the correct position.