When you restart the mobile, or when you open the app, this changes the background picture, choosing from all the images in your SD card which have in their name or in the parent folder name, the string "Wallpaper". If no image with these characteristics is found, the app shows randomly one of the predefined images.
It triggers a thread which releases the mobile for executing while searches all data in the SD card. This has the consequence of a delay in changing the image, but the mobile can still be used without interruption.
It is useful when you switch off the mobile every night and you want a surprising new image in your background.
Just put your images under a folder called "Wallpaper" and the app will use them.
Tags: wallpapers swap aaps , fondos para pantalla de estrellas , wallpaperswap