Formats

Then click onto (Format) and pick which kinda file you would like to save it as.

The format you might want to use will depend on whether its just a practice images what you not to bothered about the quality or if it your final image and you want to keep all the detail.

jpeg -This compresses your files every time you save (so it will flatten the layers)put it is still ok to use for experimental images.

Photoshop- This wont compress your files it will save all your information about the image but you might not be able to open the images on every computer.

TIFF- This can be used to save final images as it saves all the information and can be opened on any computer but it takes up a lot of memory.