Entering 30 characters is quite a lo
I will say that there is:
240000 rectangles. The image is 600x400 pixels, and since squares are a kind of rectangle, I'm going to go with that. I'm thinking its going to be more complex than that though.
Using a formula I found on a different question, the amount of rectangles found on a grid m wide and n tall is equal to mn(m+1)(n+1)/4. This gives us an answer of 14460060000 rectangles on a 400x600 grid.
Well... I will say...
Zero? None of the red shapes is a real rectangle. If you focus you can see some orange rectangles flashing inside the red shapes but that is just optical illusions.
With the lateral-thinking tag I have another answer:
240 000, the total number of pixels of this image (600x400), a pixel is a square, and a square is a rectangle.