Not unless you have a bold or italic version of that font. If you want a quick getaround for bold, just put the text on the image two or three times, one pixel off (x-1,x,x+1).
Most fonts come with italic and bold versions. Let's take for example Arial. I have arial.ttf, arialbd.ttf, arialbi.ttf, and ariali.ttf. These are Arial, Arial Bold, Arial Bold Italic, and Arial Italic respectively.
