Aha! Whiteboards | Clip images
The clip tool is ideal for quickly illustrating a UI change or experimenting with new layouts. Use the clip tool to cut out part of an image, click and drag to move it. When you clip part of an image, the background will "self-heal" and automatically match the surrounding area. This enables you to make changes to images without needing to use another design tool.
To use the clip tool:
Add an image to your whiteboard.
Select the clip tool from the image toolbar.
Draw a rectangle around the area you want to clip.
Drag the clipped area wherever you want to place it or use the Delete key to remove it.
After you have clipped part of an image, it becomes its own object — you can resize it, group it with other objects, copy and paste it, or move it independently around your whiteboard.