The major goals of this release were to improve performance, refine the user interface and experience, and to support some highly requested features such as PNG transparency support and JPEG save quality configuration.

To summarize, Paint.NET v2.1 is much faster, more compatible, and produces better quality images than v2.0. It is a highly recommended upgrade.

• Many bug fixes and miscellaneous user interface tweaks.
• Installation via Group Policy is now supported.
• Rendering quality, usage, and performance of selections is improved.
• Much better performance all around.
• Magic Wand selection tool.
• Ellipse/circle selection tool.
• PNG transparency is now supported.
• GIF save quality significantly improved.
• JPEG quality selector and preview, and file size preview.
• Upgraded PDN file format to support very large images.
• Thumbnails are now shown for .PDN files in Windows Explorer.
• Much higher quality rendering when zooming out.
• Background layer is no longer "locked".
• EXIF data is now preserved for supporting file formats.
• Lower memory usage. History items are now saved to disk instead of completely stored in memory.
• Better Tablet PC support. Also, Ink isn't used unless you have a Tablet PC; this has increased compatibility and performance on regular systems.
• Ability to resize image based on a percentage.
• Brand new image resampling routines for Image->Resize menu item (no more transparent borders).
• No more flickering in the UI.
• More optimizations for multiprocessor and multicore systems.
• Startup time is greatly reduced.