IMPORTANT: saving of PNG-files needs LOT OF OPERATING MEMORY (but almost all mobiles have small amount of operating memory). Because of it - when you drawing in 24bpp mode - ALWAYS save picture to BMP format while you not to finish your masterpiece. Because of may be situation than when you will save to PNG - PaintCAD will freeze (because of out of operating memory) and you will loose your not-saved picture. ONLY when you finish to draw - you can try to save it to PNG. And if PaintCAD freezes - you can re-launch it, open your picture from BMP and simply save it to PNG =)