iPhoto, saving small sized jpegs

[dharmit]

Hi,

Dharmit again.

I had posted my thoughts of using iPhoto comparing it to Picasa, but I am still not getting the right direction. I want to go to the path of iPhoto but till I get satisfied with whether iPhoto can do some of the things that I am doing right now, I am sticking to my Picasa routine.

My question is

1. iPhoto when saved my RAW file (before and after editing), its size was 3 to 4MB, Normally when I save my jpeg file from Digital Photo professional or UfRaw or Picasa their size is around 7MB or more. I did save it to the original resolution and original size but then why did iPhoto save it to around 3 or 4 MB?
2. Does iPhoto save it using a different algorighm than DPP, UfRaw or Picasa? If so, is it better or worse?
3. Does iPhoto save it at different dpi(ppi) settings and if so, is there a way to change it?

Thanks

Dharmit