Photoshop files

[Stoddard]

Which is easier: using a .psd Photoshop file to generate a .png file or a .jpeg file? How exactly is it accomplished?

[suwunk]

The biggest advantage over JPEG is that PNG is a lossless file format, meaning that even though it still compresses images to reduce file size, the compression method it uses does not result in a loss of image quality. You can even re-save the same PNG file multiple times without degrading its quality, whereas JPEG files look worse each time you re-save them.
Photoshop File Formats - Quick Guide (http://www.photoshopessentials.com/essentials/file-formats/)