Hi. FOR EXAMPLE IF I'M IMPORTING A SMALL BALL IMAGE (PNG) SHOULD IT'S RESOLUTION BE 1080 PIXELS FOR GOOD QUALITY ON ALL DEVICES?
72dpi and RGB color space. The resolution must be a 1x1 ratio exactly the way you want to make it appear in your game. If it is small then it can be something like 32x32px or 64x64px, if it is big then it is something like 256x256px or 512x512px. 1080 pixels would almost cover the entire screen since the native resolution of BB retina screen output is 1136x640 pixels. Hope that helps.
If my image consists only of one color and if its resolution is 1px/cm will its quality be good on all devices?
Since the resolution of the canvas automatically resizes according to the device, the best approach shoulb be somwthing along this line: - work with the lowest resolution screens when you create the character since they will keep their resolution (will look smaller on bigger displays but not streched out like other engines do) - work with the highest resolution screens in mind when you plan your backgrounds so that they visualise correctly on big and small screens alike (will show partial area on small screens)
Although it is resized in Buildbox, in Atlasses it is the original size The size has to change before passing it to BB