I'm a great downloader of brushes, tho I only use a handful. However, the size of these PShop tools (I use CS) is puzzling. Take Trimoon's splendid instruments: they range from only a couple of kilobytes to over a megabyte. Is there anything in particular that contributes to the larger size of some brushes?

My guess would be the size and resolution of the image used to create the brush.

Also, some brushes come packaged as a collection with any number of brushes included in the collection.

Another also (well a maybe) is when you change the brush around adding texture and altering the dynamics etc this would make the size bigger presumably

Palms