One of the things which zs4 can import are still images (like jpg and png files). There are many programs out there which can produce images for use in zs4 video compositions. But the most cost effective and feature rich by far is the GIMP (GNU Image Manipulation Program). We use it for a variety of things:

• It can produce nice images with gradient transparencies for use in titles or credits. We use this GIMP feature for (zs4) logos and other still graphics in zs4. In fact, the zs4 logo (outer-space strawberry) was done with GIMP.
• It can convert image formats unknown to zs4 into jpeg and png images which zs4 can read.
• It creates windows icons for programs and menues as well as icons for Unix (typically png images). In fact, most of the graphics you see on t@b websites has been done with the GIMP.

Download this program from the GIMP Home Page:
Windows Version: http://gimp-win.sourceforge.net/stable.html
Unix Versions (Linux, BSD, Solaris): http://www.gimp.org/unix/
Mac OS X: http://www.gimp.org/macintosh/