Periodically updating plugin code?
 

I've created a custom box under $navbar following these instructions, and am using it to display random thumbnail images from posts.

I've written the code to randomly select recent threads; parse the image urls; create the thumbnails; and update a table in the database. I was thinking of running this code as a scheduled task every hour or so.

I will then need to update the html code in my custom box by reading the database table in order to update with the correct image titles and hyperlinks to the relevant threads.

I was thinking that I could do the following and create a plugin. Could I include the html code in my existing generate thumbnails code; give that a name to refer to in my templates AND still run this as a scheduled task for updating? If there is a better way, or I'm talking bollocks, I would be grateful to hear of it. :)