I know it's impossible to magically "add more resolution" to a 600x600px image to turn it into a 3000x3000px image (goal: print it in around 30x30 cm). (I have done some signal digital processing math, and I know the difficulty of the problem).
But in some cases, like images with contour, drawn with MS Paint:
are there ready-to-use algorithms / software that perform better than Photoshop's resizing algorithms (I tried all of them - bicubic, etc.)?
Or even software that can reduce the staircase effect of existing pictures?