Pixelitor

Pixelitor’s saving format determines how much of an edit you can revisit. Open the image, work with layers, masks or text, and keep a PXC file when you want the layers and their settings intact. The guide says PXC is specific to Pixelitor, so use another supported format for delivery to other applications. Save As creates a separate file. For a smart object with linked content, keep that linked file as well; losing it loses the content even if the parent PXC remains. The guide still labels smart objects, smart filters and layer groups experimental, so choose the build and document structure with that status in mind.