What is a PSD File?

Photoshop got famous first because of its layers. years ago, when image editing had just started, this was revolutionary. We all of a sudden could put different parts of a photo on different layers. If you think about layers as an overhead projector you know what layers are: You can simply put different types of photos on different overhead transparencies and with those mix your own photo. That is what layers are for, move parts around.

You can increase each image by clicking on it so you can easily see all settings used.

So when you now want to save this for later use, you couldn’t without PSD format. Because the PSD format saves the single layers and does not merge everything together such as the JPG format does.

So if you want to work on an image later you should save its PSD, then it is always editable.