26 July 2010
A keyframe is a frame in Adobe Flash Professional where a new symbol instance appears in the Timeline. A keyframe can also be a frame that includes ActionScript code to control some aspect of your document. You can also add a blank keyframe to the Timeline as a placeholder for symbols you plan to add later or to explicitly leave the frame blank.
A black dot in the Timeline indicates a single keyframe. Light gray frames after a single keyframe contain the same content with no changes. These frames have a vertical black line and a hollow rectangle at the last frame of the span.
A black dot at the beginning keyframe with a black arrow and blue background indicates a classic tween.
Do not confuse keyframes with property keyframes; the Timeline icon for a property keyframe is a solid diamond, whereas a standard keyframe icon is an empty or filled circle.
To work with keyframes, insert and position them (along with property keyframes) in the Timeline to control the sequence of events in your document and its animation.
To learn more about animating, see the section titled Timelines and keyframes in the Animation Learning Guide for Flash.