Update: this post applies to Silhouette Studio version 2. If you have version 3, please refer to the updated chart here instead.
It turns out that the question about what file formats Silhouette Studio can use is not all that easy to answer, partly because the facts vary quite a bit from the official Silhouette America information. I think I got it sorted out and into chart form. Hope this is helpful to some of you. Click here for a printable PDF (applicable for V2 only).
If you need help understanding the difference between vectors and bitmaps, this video should help.