If you are working in PSE or PS with a .jpg file every time you save the file as a .jpg you will re-compress the image. and loose detail and more Jpg artifacts will appear in the image.
Batching in PSE
File > Process Multiple Files
You get this requester in PSE 8
YOU NEED to select the source and destination for the files and Set up your own renaming scheme
Choose file type… .tif
you can also do some "quick" processing, water marking the images or add a caption.
Batching in PS with The Bridge and Camera Raw!
Here's how to load more than one file into Camera Raw.
or the Command Key (Mac)
Then right click on one of the highlighted thumbnails, from the pop-up menu choose "Send to Camera Raw"
in Camera Raw (illustrated below)
Top left choose Select All (1) then Save Images(2)
You'll get a robust conversion dialogue box that will allow destination, renaming and several file types...
What's neat about this process is 1. It's really fast and 2. you can start multiple conversion sets one right after the other...
Gota a question 'holler