The Animated GIF file format has been around a long time, even predating computers that could display more than 256 colors at once! Regardless, it is a format that is supported by all web browser without needing to install anything, which is why it was the default for Pivot Stickfigure Animator and is also an exportable format from Stykz.
Be aware, though, that if you select to export to Animated GIF, you need to understand and accept the following things:
GIF images are limited to a maximum of 256 colors, so Animated GIF frames are limited in the same way. If you use more than 256 colors on any given frame, your output can appear dithered, banded, or display streaks of color or other abstracts.
Because the method used to antialias something requires making a gradual blend from the color of one object to the color of the item behind that object, antialiasing can use up your 256 color slots really quickly... you may not notice it, but if you export Animated GIFs that are showing abstracts you may wonder why it's doing that (you didn't pick 256 colors, right?) - antialiasing is probably at fault.
If you see this happening and you are on Windows, you can turn off antialiasing before you export to Animated GIF (View > Show Antialiasing). If you are planning on exporting most or all of your animations to Animated GIF, you can change the default preference for export (Edit* > Preferences >> General > Export Format). If you're on Mac, you may need to export to QuickTime, where millions of colors are supported.
Frame Delay vs. Frames Per Second (FPS)
Animated GIFs represent the speed of the animation by implementing a frame delay - that is, it tells the playback application how long to delay after drawing the last frame before it draws the next one. This is measured in 1/100ths of a second. This is very different than frames per second (FPS), which QuickTime uses to define how many frames to draw in the space of a second of animation.
The reason this is different is that QuickTime will take certain actions like dropping frames or lowering quality to make sure the animation plays at the FPS you have specified. Animated GIF will not do that; and each frame of animation may take a little more or a little less than the previous frame based on what is on the frame. So there is not a direct 1:1 correlation between FPS and frame delay (unfortunately).
Additionally, it turns out the different browsers support different minimum frame delay rates, and take different actions if you specify a delay rate smaller than what it supports. For all the details, you can read this article on DeviantArt. But it boils down to these basic rules:
- Mozilla allows 2/100 or higher, but if you set it to 1/100, it will change it to 10/100.
- Internet Explorer allows 6/100 or higher, but if you set it lower, it will change it to 10/100.
- Opera allows 10/100 or higher, but if you set it lower, it will change it to 10/100.
- Safari allows 3/100 or higher, but if you set it lower, it will change it to 3/100.
IMPORTANT: Although you can set the frame delay to any amount you like, for best compatibility, you should not set the frame delay any lower than 6/100ths of a second.