So i'm programming python program that uses wxPython for UI, with wx.TreeCtrl widget for selecting pictures(.png) on selected directory. I would like to add hover on treectrl item that works like tooltip, but instead of text it shows bitmap picture.
Is there something that already allows this, or would i have to create something with wxWidgets? 
I am not too familiar with wxWidgets, so if i have to create something like that how hard would it be, lot of code is already using the treectrl, so it needs to be able to work same way.
So how would i have to go about doing this? And if there might be something i might be missing id be happy to know.
Take a look at the wx.lib.agw.supertooltip module. It should help you to create a tooltip-like window that displays custom rich content.
As for triggering the display of the tooltip, you can catch mouse events for the tree widget (be sure to call Skip so the tree widget can see the events too) and reset a timer each time the mouse moves.  If the timer expires because the mouse hasn't been moved in that long then you can use tree.HitTest to find the item that the cursor is on and then show the appropriate image for that item.
wxpython treectrl show bitmap picture on hover