I came across a great graphics program recently called Gravit Designer. I wouldn't say it's the best but it's quite simple and for me, that's what makes it great. It's great to make some quick graphics for your website or blog especially if you aren't great with graphics design. The best aspect, of course, is its simplicity. There's nothing complicated about the buttons, you could spend 5 minutes and learn all the functions that you need to use.