The poster that I sent that to said that optimizing and file conversion were not the same.
I don't think it is the same. It could be, but not necessarily. Optimizing would be a conversion, but conversion of a file could be many things, optimizing being just one of them.
Please post a link, I'd like to take a look at the source of the info.
Thanks
The only ways to do it are to adjust the image size or convert it to a different format. .jpg's are to pictures as mp3's are to music, they are compressed files. Both formats are simply compressed, optimized file with minimal quality loss. That is way it is "optimal"
This was my source link, there are thousands of them out there.
Or go to htmlgoodies.com, there is everything you could ask to learn there.