Photopea is a free online photo editor that supports a variety of formats including PSD, XCF, Sketch, XD, and CDR (Adobe Photoshop, GIMP, Sketch App, Adobe XD, and CorelDRAW). You can use it to create a new image or open existing files from your computer. Your work can be saved as a PSD file (File - Save as PSD) or exported as JPG, PNG, or SVG (File - Export).

Using it feels like using Photoshop, and there are no annoying pop-up ads, just three fixed ads on the right side. If you need to make temporary modifications to some images and don't want to install software, you might as well try this website.