dotPDN LLC has unveiled Paint.NET 4.3.1 for Windows PCs. It follows a mere five days after the major 4.3 update, and fixes some problems introduced with the new version.

These include resolving an issue with the Explorer 'Open with' menu, which primarily affected Windows 7 and 8.1, but also some versions of Windows 10, as well as repairing image thumbnails when using File Explorer’s Details View.

Paint.NET 4.3, released last week, came with some major performance optimisations, and also unveiled a new portable build for those keen to minimise their system footprint or use the program on the go.

Many performance enhancements are down to the app’s migration to the .NET 5 platform, which should deliver a noticeable 20% improvement on all compute-intensive tasks such as applying effects.

Other improvements can be found when drawing using the various tools – these are faster thanks to large parts of the app being optimised to use SIMD (SSE2/3/4.1, AVX2) on x86/x64 platforms. In addition, other areas of the app also benefit from tweaked settings to deliver better performance.

Those installing the app through the Microsoft Store should benefit from improved startup times, while native support for ARM64 means users of compatible devices such as Microsoft’s Surface Pro X should also enjoy major performance gains.

The migration to .NET 5 also removes the need for users to install .NET separately on their systems thanks to the fact Paint.NET has been published as a self-contained app, which means all required runtimes, libraries and dependencies are included within the app package.

The new portable build is distributed separately to the installer – it’s a self-contained zip file that users simply extract to their desired location, whether that’s a dedicated folder on their system drive or a USB drive for running on any compatible PC.

Elsewhere, there are minor improvements to the quality of selection antialiasing thanks to the use of a 4x4 super sampling filter. Users also gain the ability to organise Effect and File Type plugins into separate sub-folders to make them easier to organise. Plugin stability has also been improved by loading them into separate AssemblyLoadContexts to prevent instabilities causing wider problems.

A full list of changes can be found on the Paint.NET roadmap and change log. Paint.NET 4.3.1 is available now as a freeware download for PCs running Windows 7 SP1 or later. Existing Paint.NET users should be prompted to update to 4.3.1 shortly, while a paid-for version can be purchased via the Microsoft Store as a means to supporting further development.

Also newly available is Paint.NET Portable 4.3.1, which is distributed as a self-extracting zip archive, and requires updating manually each time.