After you edit an image in Photoshop Elements, ensure that you save it. To ensure that all the image data is preserved, save regular images in Photoshop (PSD) format. Multiple-page creations are always saved in Photo Creations (PSE) format. These formats don’t compress your image data.
Save your photos in PSD format (instead of JPEG), unless you plan to share your photos or use them in a web page. Each time you save in JPEG format, the image data is compressed, potentially causing some data to be lost. You may start to notice reduced image quality after saving the file as a JPEG 2‑3 times. The disadvantage of saving in PSD format is that the file size increases significantly because the file is not compressed.
Photoshop Elements can save images in several file formats, depending on how you plan to use them. If you are working with web images, the Save For Web command provides many options for optimizing images. To convert several images to the same file format, or the same size and resolution, use the Process Multiple Files command.