Final answer:
To reduce file size, adjust the resolution and compression settings for the images.
Step-by-step explanation:
To reduce file size for all scaled images in a presentation, you can adjust the resolution and compression settings for the images. Lowering the resolution and increasing compression can decrease the file size while still maintaining reasonable quality for screen display. You can do this by using photo editing software like Photoshop or Pixlr Editor to compress the images after taking them or by adjusting the settings on your digital camera before taking the photos.