My understanding is that unless you have taken the image in RAW format, there will always be loss of clarity.
And afaik, RAW format is really only available on high end digital cameras like Nikon or Cannon.
The other problem with RAW format is that it takes up an enormous amount of storage space.
Most of the pics taken with the average cell phone look great on web pages where they’re relatively small in size but would look terrible blown up to 8X10 size.