How do I resize a image preserving aspect ratio in After Effects? In my compossition I imported an image, I would like to scale the image in real-time (I mean using the mouse to select the image, center it in the composition and resize it to see the results in real-time because for me is more productive to do it in this way, instead of manually specifying width and height wherever) preserving the aspect ratio of the image.

In Photoshop, this can be done by clicking in a corner of the image element then holding the CTRL key while using the mouse to resize the image, so the image is scaled preserving aspect ratio, however, I can't reproduce this behavior in After Effects, if I do click on a corner of the image, nothing happens.

If this is not possible to do in the same productive and easy way than Photoshop, then how I could do it (in the less tedious way)?.
Click on a layer name. You should see the control points on its border. Click on one of the border points but don't drag it yet. Hold down Shift key and then drag it. Release the mouse button when done and then release the Shift key.