In your file format Associations do you have .png selected as an associated file type?
I see that .pic is right above the .png in my list. I wonder if a file type is not associated if it will pic the next one up on the list (because they are in alphabetical order) I don't have .pic checked as being assocaited and yet I can see it in my choices when I do a save.
oops just read Jane's response...
Great minds think alike!
What makes you think it is compressing your file, if I choose to save as a .pic I do not get any options to compress that file type (My options) button is grayed out.
If I save as a .png I get options to optimize it. If you don't want it optimized or compressed don't use the Option button, just pick .png in the save dialog box and click save.
I also don't undestand why you are saving them as .ppm files first either, you can save anything as a .png. Then main benefit of .png files is that they will hold and display a transparent area around a image. But for a image that covers the canvas from side to side it really isn't nessecary using that file format unless it is something different you are doing with them.