Need to import smoothiboard from github

While I'm not an expert, I don't think there is a quick fix. This isn't a Fritzing part, it is (as the title suggests) the png graphics of the board. While a Fritzing part could be made with the png as a base it would be a fair amount of work. With no updates for 2 years it looks like the original author has given up. Basically you (or someone) would need to define where all the pins on the board go to create a part (none of which on a quick look appear to be in the repository). Hopefully someone else has a better answer for you