[Hampshire] Hidden folder

I have a hidden folder in my home folder called .thumbnail, within this folder
there are two other folders called large and normal. As the name suggests it
holds thumbnail pictures of pictures I guess I have opened on my system. Now
this folder currently stands at 1.6gb in size, some 31600+ files

So my question is, do I need this folder?? can I control its size and if so
how??

I am running Mepis 7 with KDE 3.5.8 if that helps

Tim