Drawing Curves in Flash with the Pencil Tool
When you use the pencil tool to draw curves in Flash, your lines are drawn in pixelated format which can end up taking more space than a similar curve using the pen tool. The solution to this is to use the Optimize option in the Modify > Shape menu to optimze your curves. The smoother you make your curves, the smaller they will be. Be careful that you don't over smooth them and completely change the shape.
Solid Lines in Flash Use Less Space
Special line types, like dotted, dashed, ragged, etc. take up more memory than solid lines. Unless you have a distinct reason for them, avoid special line types for a smaller document.
Flash Groups and Layers
Grouped elements will take up less space than elements that are separated. And when you animate your images, separate the items that don't move onto a different layer than the elements that do move. That way, your Flash document won't repeat the non-moving elements and make your document larger than it needs to be.
