But, do you know that GIMP can be used to manipulate animation too? Well, this isn't a joke. GIMP is able to do that, but you need a package called GAP (GIMP Animation Package). It's a collection of plug-ins to extend GIMP with capabilities to edit and create animations. You can grab it from GIMP's FTP site, but if you used Slackware, i have created the SlackBuild in Indonesian Slackware Community site.
All you need to compile this application is the SlackBuild, the slack-desc and of course the source code of the GAP package itself. After you downloaded all of them, switch to root user and ran the following commands
chmod +x gimp-gap.SlackBuilds
After doing this, you will have gimp-gap installed on your system and you can start making animation. You can also look for the option i used for the configuration phase. I disabled some feature since it's not included in the default Slackware installation, but it's not a critical features. I'm trying to make it work in the default Slackware 12.0 installation. If you have installed some multimedia libraries, then you might be able to tweak the option i used to have more features.
By default, you will notice that GIMP will add new menu under Xtns called Split Video into Frames and it has several sub menus again. You also had some option to create new file based on video templates (you will have PAL and NTSC). Look at the lower right at the screenshot