Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Online Image Editor - Online editor for images and animated gifs with multiple effects and tools
SVGO - Tool for optimizing SVG files
Krita - Krita is a professional FREE and open source painting program. It is made by artists that want to seaffordable art tools for everyone. Concept art. texture and matte painters, illustrations and comics.
SVGminify.com - Removes superfluous information reducing the size of SVG files
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.