If I want to resize a layer in photoshop I cmd+T, hold down Shift and drag a corner so it doesn't skew it in the process of resizing. How do I accomplish the same thing on GIMP?
There's the Scale tool. If you hover the cursor over it, it advertises to operate also with layers.
- zoom out the image to be smaller than your screen
- select the layer
- drag by the Scale tool the corner holding Ctrl at the same time
You must accept the resizing in the dialog that opens without asking.
NOTE: if you do not drag, only click, you get the same dialog. You can enter for example: link x and y, new size = 50%