Really? What file format would you recommend?
That description was taken from a we site to illustrate that converting files is indeed optimizing photos.
The poster that I sent that to said that optimizing and file conversion were not the same.
.jpeg is a good format but can slightly dull the edges in certain circumstances due to the compression, not that the casual observer would ever notice though.
Most graphic artist are anal about things like that, hence the description of .jeg