Difference between saving as jpg and png

[Simontam]

What are the major differences in saving as png vs. jpg? I've noticed some key differences in how the alpha channel appear as well as how the shadow files are treated Obviously png's have built in transparency but it appears I can never get the proper shadow channel output when I save as PNGs.

I hope that there isn't any loss of quality either when I save out the channels as jpg.

[Neilg]

There is, .jpg is lossless.
.png cuts your alpha out too, use .tiff or .exr

[Neilg]

Lossy, it changes the image. Sorry, it's early and for some reason I dont have an edit button.

.png, .tiff & .exr are lossless - meaning they compress without changing the image.

[Morbid Angel]

Lossy, it changes the image. Sorry, it's early and for some reason I dont have an edit button.

.png, .tiff & .exr are lossless - meaning they compress without changing the image.

Correct. We still use jpgs for textures though, if you have many many textures, jpegs are smaller file sizes though compressed load faster on the network.