You can import an image sequence into Motion as long as each file in the sequence contains three or more numerical digits in its filename; for example, image.001.tif, image.002.tif, image.003.tif, and so on—or file00001.jpg, file00002.jpg, file00003.jpg, and so on.
Image sequences store video clips as individual still image files. Each image has a number in its filename that indicates where it fits into the sequence. In a film clip that's been digitally scanned, each file represents a single frame. In a video clip that's been converted to an image sequence, each file contains both fields of a single video frame, with the upper and lower lines of the image saved together.
Image sequences can come in the same file formats as still image files. Some of the most popular formats for saving image sequences are:
Like still image formats, many image sequences support alpha channels, which are automatically used by Motion. Because image sequences have been around for a long time (before QuickTime, they were the only way to store video on a computer), they remain the lowest-common denominator file format for exchanging video across many different editing and compositing applications.
While QuickTime is increasingly used to exchange video clips between platforms, image sequences are still in common use—especially in film compositing. As with QuickTime video clips, you can mix image sequences of different formats, frame sizes, pixel aspect ratios, frame rates, and interlacing.