You can assign an image sequence to an image plane in order to create an animated background in your scene.
To create an animated image plane using an image sequence
This automatically enters an expression (=frame) into the Image Number attribute. The Image Number is equal to the Time Slider’s current frame.
If you want to animate your image sequence with "non-standard" logic, you can edit the expression on the Image Number attribute (right-click Image Number and select Edit Expression) and enter the desired changes. For example, if you wanted to slow down the image sequence to "playback" at half speed you could add a divide by 2 to the expression.
Alternatively, you can remove the expression from the Image Number attribute and set key frames on the Image Number attribute just like you would animate any other attribute. This way, you can animate the sequence with more complex logic such as reversing the image sequence or holding the first frame, then "playing" and then holding the last frame.
You can also assign a movie file to an image plane to create an animated image background; however, using an image sequence is recommended because not all movie file formats are readable in Maya Creative’s image planes. For example, on Windows, only .avi files are accepted.
To create an animated image plane using a movie file
To add file formats