Photos: decrease in quality when exporting a live photo as a gif

The GIF format was never designed to be for photos and by definition only allows 256 colours. From Wikipedia, GIFs are used as follows:

  1. GIFs are suitable for sharp-edged line art (such as logos) with a limited number of colors. This takes advantage of the format's lossless compression, which favors flat areas of uniform color with well defined edges.[23]
  2. GIFs may be used to store low-color sprite data for games.[24]
  3. GIFs can be used for small animations and low-resolution video clips.[24]