Was messing with export options for some sprites and decided to turn them to jpeg with 0 quality just to see if that works in preivew. Turns out it doesn't - all sprites are high quality as usual. True quality shows up only after export and that's understandable cause compression takes additional time.
But my question: how do I preview a project with compressed sprites? Is it possible? If not then we miss a necessary option cause we won't be able to analyze the game properly at least on phones and tablets(I think so).
Oh and a sub question - does jpeg or PNG-8 compression help increase performance on mobile devices?