imageGif

I've used this function imageGif only with first parameter.
like a imageGif($img);
Have a question, did any temp file anyway created?
i have two servers, all on FreeBSD OS.
On first one, there is all ok, but on the next one i have
a lot of temp files in /var/tmp with GIF content.
These temp files are growing days by days, what function
can do it?
Anybody, help!