I always use png files when saving in Poser to take into my graphic program. 

I do alot of single renders that require no background, so .png is ideal because it opens into any graphic program backgroundless (unless of course you saved it with a background in place).  With a .tiff format, you have to apply a mask of the image to itself to remove the background.

And as others have said, .jpg images always have quality loss because the file is compressed, even at 100%. And the more often you save a .jpg file the more loss you experience because the compression is cumulative.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi