It’s the Friday Puzzle!

Please do NOT post your answer, but do say if you think you have solved the puzzle and how long it took. Solution on Monday.

How many triangles are hidden in this image?

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.