1. Choose a texture for your brush, and at ,,Texture browser...,, unselect the ,,Kingpin Textures,, texture folder (click anywhere on white space), click ,,Folders,, and ,,New main folder...,,
Click ,,In a new Add-on,, to make a new .qrk addon, with a name (for example your username_textures). The addon name must not be long.
2. Now you have a ,,New folder,, and give this the same name as the created .qrk addon.
On the left of the binoculars icon click ,,Make links to textures in a folder.,,
Click ,,main,, on the list and leave thicked only ,,Dynamic,, and ,,Merged,, and click ,,Ok,,
Click + of the ,,main,, list and delete everything except your texture folder.
3. Drag your texture folder name in the list on the ,,username_textures,, and delete the empty ,,main,,.
Now you have a new structured list as above. Close Quark and save.
Move the .qrk addon in Quark ,,addons,, folder if you want.
Enjoy your textures or textures with transparency. :)