Recently, I found that my sdcard become full suddenly.
I remeber that I must have more than 1G left. So I am looking for which directory are growing too quick.
Finaly, I found that it is coming from /mnt/sdcard/Android/data/com.cooliris.media/cache.
This directory contain more than 1G files. So I delete them to free up the memory.
However, it is growing up quick to use up all the memory in my SDCARD.
At last I found our the reason. It is coming from cache for my comic. So I added .nomedia in all of my comic and the problem solved. It is now only around 50M.