Sketch - Professional digital design for Mac.
Rasterbator - Wall art from any image
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Posteriza - Use POSTERIZA to design your own big posters and signs from any digital photo with your home...
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
Block Posters - A free poster maker to create massive wall posters from your own images! Free!