Use percentage adjustment
Select a picture, shape or wordart to resize, and enter "Picture Format" or "Shape Format >". Location > layout options ". Click Size, and under Zoom, make sure Lock Aspect Ratio is selected. Enter the desired Height and Width percentages. For example, enter "50" to reduce it to 50% of the original image!
Resize freely
Select an object and hover over an edge or corner until four arrows appear. Hold down the left button and drag the arrow to resize. Hold down the Shift key at the same time to easily lock the aspect ratio!
Using the Picture Size dialog box
Right-click the selected object and select Picture Size. Specify the height and width in the dialog box. Check or uncheck Lock Aspect Ratio as needed.