As the title goes, I want to know how to enlarge the imagesprite over time.
Increase the imagesprite height and width using a clock and additional variables (e.g. +1 each iteration)
Why do you add 1?
Your clock timer interval will probably remain the same, for example 1000msecs (so the clock fires every second. This is just an example, you may want a different interval)
Then in your Clock Timer Event block increase the size of your imagesprite:
set imageSprite.Width to imagesprite.Width + 1
set imageSprite.Height to imagesprite.Height + 1