圖像處理軟件Paint.NET v4.2.0 Final
Paint .NET 是一个免费的图像和照片处理软件，它由由美国华盛顿州大学开发，是微软官方支持的一个高级研究生设计项目成果。Paint .NET 开发初衷便是为用户提供一个免费的强大的微软绘图板替代软件，现在逐渐发展为一个功能强大且易用的的图像和照片处理软件，已经获得不少专业用户的青睐，成为主流图像编辑选择之一。
它功能强大，支持图层、Clone Stmap、Edge Detection、Motion Blur及History等无限制的历史记录、特效以及许多实用工具，并且开放源代 码和完全免费，界面看起来有点像Photoshop。该软件的开发语言是C#[1] ，在 .NET Framework 环境（事先需要安装）下运行。支持简体中文等多语系界面。
最初作为一项计算机高级图形设计项目，Paint. NET在2004年春由华盛顿大学被提出。在概念提出及维护者Rick Brewster的不断努力下，其功能不断加强，并在2004年下学期得到进一步发展。 目前，Rick Brewster在微软工作，当然，其最初成员也有来自微软及受微软赞助的背景，这使得Paint. NET开始受到人们的日益瞩目。下面让我们在最新公布上的Paint. NET v2.5 Beta 4版中，一起来品味Paint. NET的疯狂与梦想。
Paint. NET工具面板与PS的感觉比较一致，其基本功能如选取、移动、魔棒、文字、色彩吸管、克隆、画笔、橡皮、颜色替换、刷子、直线、矩形、椭圆等共20项。就数量和各工具的调整参数而言，与PS差距不小，不过满足日常的基本应用应该没有问题。
在Paint. NET中，各项工具的使用方法与PS基本保持一致，比如克隆工具，均采用Ctrl+鼠标左键定义“源”，并使用鼠标左键进行克隆。
Paint. NET的范围选取工具包括矩形、椭圆、套索、魔棒。当选定范围时被选定区域显示为浅蓝色，同时区域边沿会有运动的点画线标识，动态效果十足。
文字功能在Paint. NET中显得比较弱，字体格式调整的参数几乎空白。不过Paint. NET对中文字体支持比较好，笔者安装的数十种字体均可以正常显示并应用。字体工具中与PS中使用习惯不同的是其移动方式，在Paint. NET中添加的文字右下角会出现一个十字光标的按钮，点击该按钮可以轻松移动文字对角，使用起来极为方便。
“层”概念的引入使Paint. NET有了质的提升，新层可设置名称、显示与否、混合模式（7种）、透明度（0-255）等参数。
历史面板的功能在Paint. NET也较为突出，只要你的硬盘空间足够，Paint. NET支持无限次“后退”操作。
作为重要的创作的工具，笔刷的样式在Paint. NET中提供了50种，可以满足更多人的需要。不过，说实话，在使用中Paint. NET的笔刷效果依然给人一种意尤未尽的缺憾。
几何绘图工具在Paint. NET中包括直线、矩形、圆角矩形、椭圆和自定义形状（很可惜多边形工具没有）。根据工具样上的三种模式选取，可以创造出更多的变化。
简单直观的用户界面
Paint. NET 使用 Windows Aero 界面，具有立体感、透视感，使用户拥有了家的感觉。另外由于其简单直观的界面，使用户很容易找到自己需要的工具。两侧共有四个窗口——工具、历史记录、颜色和图层。用户可以在窗口顶部的下拉菜单中自行选择删除或添加。
键盘快捷键
熟悉PS软件的人都知道，它支持许多键盘快捷键，而Paint. NET 也支持。当鼠标悬停在一个工具上时，就会显示出该工具的名称以及所代表的快捷键。
Paint NET 性能
Paint. NET 运行很快速，不管你是哪种类型的电脑，Paint. NET 运行速度都很快。不过这也不能说明它就不会出现崩溃现象，目前只希望它能继续保持下去。
在线社区
Paint. NET 最大的特色就是有一个活跃的在线社区，用户之间可以进行交流和讨论问题。在Paint. NET论坛上有两个主要特点就是教程和插件。在线社区是一个不错的主意，相信这会帮助用户及时的解决问题。
Paint NET 特殊效果
Paint. NET 图像编辑器上有大量的特殊效果，从增强图像效果（包括调整图像的对比度和色彩）到去除红眼等，这里就不再一一列举了。如下：
1、原始图像
2、膨胀效果
3、软化写真效果
4、铅笔素描效果
各种强大的工具
Paint. NET 不只具有特殊的效果，它还拥有各式各样的强大工具。从3.0新版本的渐变工具到着色工具。如果你不会用某项工具，还有教程可以帮助你。
历史记录
处理图像的每个动作，都会在历史记录上进行存储，你可以不停的“撤销”与“恢复”。有时候因画错了一个地方而感到很沮丧，但是通过历史记录可以进行挽回。不过小编在这要提醒一句，如果你是一名设计人员，尽量还是少用该功能。
免费
免费的工具总是能得到用户的格外青睐。
更新日志
v4.2.0:
New: Support for loading and saving HEIC images (Windows 10 v1809+ and codec installation is required). Please note that the “Quality” slider when saving is limited to a value of 90 (out of 100) while Microsoft investigates and fixes a crash in their codec.
New: Keyboard shortcuts for changing the current layer. You can see these in the Layers menu with the “Go to …” commands. Alt+PgUp/PgDown will go to the layer above/below, and Ctrl +Alt+PgUp/PgDown will go to the top/bottom layer.
Fixed: Optimized rendering engine to remove huge lag spikes (30+ seconds) when zooming or panning very large images (eg 32K x 32K pixels).
Improved: BMP now supports saving in 32-bit (with alpha!) and 8-bit indexed.
Improved: Added DIB and RLE file extensions to the BMP file type.
Improved: PNG, JPEG, and TIFF now support loading and saving of much larger images.
New: PNGs can now be saved as “interlaced”.
Improved: JPEG now has configuration for the chroma subsampling mode (4:4:4, 4: 2:2, and 4:2:0). The default is now 4:2:2 instead of the unconfigurable 4:2:0 of older versions. This may result in larger file sizes, but higher quality, as compared to previous versions.
Improved: TIFF now supports saving at 24-bit and 8-bit color depths.
Improved performance of saving for file types where “Auto” bit-depth is supported but is not the current choice.
Improved temporary memory usage when saving images at 8-bit color depth.
Improved: TGA images now load about 4x faster (thanks @null54!)
Fixed: 8-bit TGA images should now load correctly (thanks @null54 for the fix!)
Fixed: Some 32-bit TGA images were showing up as completely transparent due to their use of an obscure alpha channel type (thanks @null54 for the fix!)
Improved: Added error reporting to the Save Configuration dialog. Instead of just saying “Preview: (error)”, you’ll also get the standard error dialog that includes the exception which can used for troubleshooting.
Fixed a number of performance issues in the Save Configuration dialog. Especially with large images, it should now be much faster to change options and to click OK/Cancel.
Fixed flickering in the Save Configuration dialog when changing options.
Fixed: Windows Explorer thumbnails for some image types (PDN, DDS, TGA) were not rendering their alpha (transparency) correctly, resulting in color skew. You may not see the effect of this fix for a particular image until that image is resaved or you clear Explorer’s thumbnail cache.
Fixed: Mouse cursors now scale appropriately for non-integer UI scales (eg 125% or 175%)
Fixed: AltGr should now work correctly with the Text tool. It will not trigger shortcuts like File->Save All , or Edit->Paste into New Image. (thanks @Bruce Bowyer-Smyth for the fix!)
Changed: Image->Resize supports Super Sampling again, and favors this over Fant when using Best Quality. Fant is still available, but is no longer chosen automatically.
Changed: Holding Ctrl when starting to move a selection with the Move Selected Pixels tool will no longer leave behind a copy of the selected area
Fixed: Bicubic resampling in the Move Selected Pixels tool was not correctly handling the alpha channel in some cases. This fix has required a reduction in performance.
Improved: When using Edit->Copy, a 32-bit BGRA bitmap in the DIBV5 format is now placed onto the clipboard so that other apps can read the alpha channel.
Improved: When using Edit->Paste , DIBV5’s are now supported if they have an alpha channel. If they don’t, then the regular DIB loader is used which has some heuristics for detecting an incorrectly defined alpha channel and correcting for it.
Improved: When using Edit->Paste, PNG is now the highest priority format. This maximizes the ability to maintain alpha/transparency, but it does mean that images coming from Microsoft Office apps will appear larger than they used to. This is either a bug or a feature of Microsoft Office. For some reason it places PNGs on the clipboard that are 25%+ larger than the DIB/DIBV5 bitmap that it also places on the clipboard (but which don’t have alpha/transparency).
Fixed: DIBV5 bitmaps should now work with Edit->Paste, which improves alpha channel handling. (thanks @null54 for the fix!)
Fixed: Top-down DIBs should now work correctly with Edit->Paste. (thanks @null54 for the fix! )
Improved CPU usage for thumbnail updates (layers and image tabs) in many cases.
Improved: Slightly increased the size of the Settings dialog to reduce the need for scrolling in a few important situations
Fixed: Simple message boxes can now be closed with the ESC key
Fixed: Magic Wand now works on very large images (eg 65535 x 65535 pixels ) without an error.
New: Plugins that use IndirectUI can now use a UriProperty with a LinkLabel control (thanks @null54!)
New: Effect plugins can now more easily make use of the clipboard via the IClipboardService. It will handle all of the tricky clipboard issues such as threading, native data marshaling, and avoiding security vulnerabilities that exist in the standard WinForms and WPF clipboard APIs.
New: FileType plugins can now specify separate lists of extensions for loading and saving.
Blocked the WebP FileType v1.1.0.0 plugin due to instability. An update is already available.
Blocked the ImAgif FileType v0.12.0.1084 plugin due to incompatibility. An update will hopefully soon be available.