air skin tree icons

The page icon in a tree with the air skin, looks almost like a checkbox. Is it possible to make some changes so that it looks more like a page?

Perhaps add a border line to the page flap:
http://www.bauerapps.com/files/air_skin_page.png

You can replace a page icon with custom one. It can be done for specific tree all for all tree controls. Check the next snippet

http://webix.com/snippet/33efe9c9

Great, thanks

PS: what tool did you use to convert the png to a base64 string?

http://websemantics.co.uk/online_tools/image_to_data_uri_convertor/

Probably it is not the best tool, just a first result from google search.