CADEMIA Community Edition
CADEMIA is an Open Source CAD system with features including graphical/drawing attributes conforming to standards, flexible input, macro management, associative dimensioning and more.
PngOptimizer
PngOptimizer makes your PNG files smaller and removes useless/wrong information from them. It is also able to convert BMP, GIF or TGA files to the PNG format using simple drag-and-drop. You can also paste a clipboard image straight into PngOptimizer and get a PNG file directly.
ArtRage Starter Edition
Free painting software, that lets you draw on virtual canvas, using virtual drawing tools and produce a realistic painting.
Paint.NET
Paint.NET is free image and photo editing software for computers that run Windows. It features an intuitive and innovative user interface with support for layers, unlimited undo, special effects, and a wide variety of useful and powerful tools.
Requires Microsoft .NET Framework
Visualizer Photo Resize
Visualizer Photo Resize is a free batch resizer, converter and optimizer, that is designed to handle all your photos and graphic documents (JPEG, GIF, PNG, BMP, TGA, TIFF, PSD, PSP). The software will even allow you to embed a text watermark in the batch process. You can modify the alignment of your watermark and manually enter the edge position. You can change the font, font size and font color, and you can change the transparency of the font. Visualizer Photo Resize will also let you draw your images directly on a background canvas, so you never have to worry about different ratios for your images.
Imagicon
Imagicon is a graphics utility designed to convert multiple image files from BMP, JPG or PNG image formats into any of the following image formats
Windows or OS/2 Bitmap (BMP)
Independent JPEG Group (JPG)
Portable Network Graphics (PNG)
Windows Icon (ICO)
Dia
Dia is free open source general-purpose diagramming software, inspired by the commercial Windows program “Visio”, though more geared towards informal diagrams for casual use.
It currently has special objects to help draw entity relationship diagrams, UML diagrams, flowcharts, network diagrams, and many other diagrams. It is also possible to add support for new shapes by writing simple XML files, using a subset of SVG to draw the shape.
Dia can load and save diagrams to a custom XML format (gzipped by default, to save space), can export diagrams to a number of formats, including EPS, SVG, XFIG, WMF and PNG, and can print diagrams.