FSEvents API and kqueue caused the real memory go up fast and app hang up

Question

I want to monitor the change of folder. I can use FSEvents or kqueue as well, but the problem is memory go up so fast (more than 2GB for a tiny app) when I monitor a folder which lot of JPG images(I tested with 100 Photos). I see lot of ImageIO was allocated when profiling with Instruments.

Here is screenshot of Instruments.

I dont know why the ImageIO was allocated so much here.

I got kqueue tutorial from here: http://www.davidhamrick.com/2011/10/09/kqueue-in-cocoa.html

Any experiences, guide or suggestions would be appreciated.