Quality of downloaded images

I'm new to this, so forgive my ignorance. I want to download some jpeg images from the Internet to use in a Powerpoint presentation, but some of the images are small and of poor quality when I put them into Powerpoint. Is there any way to improve the quality?
K

Probably not in a meaningful sense.
You can try upsampling (adding pixel dimensions) with Image Size, Resample: On, but don't expect too much.

Mac