Slow loading times with masks

Hello,
I am experimenting with masks for the first time. So far I have set six masks on different images. I am getting significant loading times (several seconds) now when starting the app. I checked to make sure that it was not the images (they are large) that was causing the slow load time. With the masks removed, there was less than a second of load time.

So it is definitely the masks. Why would this be? Is there anything I can do to improve load times when using masks?

Thanks,
Scott [import]uid: 79834 topic_id: 31043 reply_id: 331043[/import]