file types
Fascinating Look At What’s Really Going On Inside A JPEG | Color, Compression, Uses
Kishore Sawh
This is detailed insight into the science of the JPEG, which while intense, may give you a better understanding of why we use it, and when not to.
Photoshop Playbook: Image File Formats Explained: When To Save As What
Kishore Sawh
Here's some help on understanding the different file formats in Photoshop and when to save your image as what type.