While using images as fills offers convenience for quickly applying visuals to shapes, it limits your flexibility in editing. Masks provide more precise control over the image's visible area, allowing you to move the image to select the exact area you want visible. In contrast, fills are less versatile. When an image is added as a fill to a shape, you cannot specify which area of the image is visible if the image is larger than the object. This makes fills less suitable for detailed design work where the focus is on a specific part of an image.

To add a mask over an image in Figma:

1. Place the image on the canvas.
2. Select both the image and the shape you intend to use as a mask from the Layers panel. Ensure the shape layer is beneath the image layer.
3. Choose Use as mask from the right-click context menu or by clicking the ellipse sun icon at the top of the Design panel.