The aptly-named Paint.Net PSD Plugin is one of those pieces of software which pretty much spells it all out right in the name. It’s a plugin…for Paint.Net…(wait for it)…which lets you open files saved in Photoshop’s PSD format.
Download the zip archive, dump the included PhotoShop.dll file into your Paint.Net FileTypes folder (usually c:\program files\Paint.Net\FileTypes), and you’re ready to rock. Pretty well anything in the PSD for which Paint.Net has an implementation will load just fine. Saving is another story, so you’d best stick to Paint.Net’s native .PDN file when you’re done working.
If you don’t have Photoshop, the plugin is a handy for looking at PSDs your friends might send you to look at. It’s also a nice way to transition yourself to a free alternative if you no longer require Photoshop.
If Paint.NET is your editor of choice and you find yourself needing to open .PSD Photoshop files, this plugin will help you introduce .PSD images into your Paint.NET workflow.
The plugin doesn’t replicate all of the numerous functions of the .PSD file, just the ones that relate to functionality within Paint.NET. You can work with layers, load masks, and open a variety of color modes and profiles. Because of the limited integration with the .PSD file, the plugin is best suited for pulling a .PSD file into Paint.Net and converting it to be used in your Paint.NET workflow. Working with it in Paint.NET and then trying to bring it back into Photoshop is a bit dicier as far as compatibility goes and can have unexpected results. PSDPlugin is free and required Paint.NET 3.0+.