CUSTOM BOOT SCREEN - put your own picture on the PowerPlay's power-on screen
============================================================================

1. Put ONE picture in this folder (custom_boot_image).
2. Double-click "Make Custom Boot Screen.bat" (one folder up).
3. Copy custom_boot_image\ready_for_sd_card\powerplay.bin to the root of the SD card and update
   the PowerPlay the usual way. Check "preview (what the screen shows).png" first if you like.

Picture specs
-------------
  File type     JPG or PNG (BMP, GIF, WEBP and TIFF also work). If several pictures are in the folder,
                the newest one is used.
  Shape         4:3 landscape fills the whole screen. Best size: 800 x 600 or 400 x 300.
                Anything else works too: the whole picture is shown (never cropped) and the empty
                sides are filled with the picture's border colour (if the border is one flat colour,
                for example a logo on white), otherwise black.
  Screen        The screen shows it at 320 x 240, so keep text big and bold: at least 1/15 of the
                picture height (40 px on an 800 x 600 picture). Thin lines and small text blur.
  Edges         Keep important things a little away from the edges.
  Transparency  Transparent parts of a PNG show as black.
  Colours       Normal RGB. Simple artwork on a flat background looks sharpest; very busy photos
                get compressed more to fit (the boot screen holds at most 32 KB).
  Photos        Phone photos are turned upright automatically.
  Animated GIF  Only the first frame is used.

What you get: your picture stays up for about 2 seconds at power-on, then the live picture.
It replaces the loading-dots animation. To go back, flash the original powerplay.bin again.
