Uploading Images and PIL

[Take Satoh]

Hello,
I recently developped a simple cgi to
handle file(image) upload with PIL(Python Imaging Library).

It really works fine, PIL is a nice work!
and now I have a question.

My cgi program deal with uploaded data as following and
I am wondering wheather
there is any possibility that some commands may run on
server by uploading unexpected data by malicious clients.

I think some image formats may contain script inside
and some might be executed when "Image.open()" is called.

Is above correct?  And is it safe to disclose following code to public?

---------------
import Image,cgi;
.....
u_file=cgi.FieldStorage()["fieldname"];
im=Image.open(u_file.file);
im=im.resize((150,120));
im.save("filename");
----------------