I'm trying to set an icon for my app, however the icons derived from the original image are pixelated and look bad. I tried to provide the app icon gear application with images of different sizes, however the result is still unpleasant.
Should I provide it with images of higher resolution or lower resolution to get better results?
The answer to this question links to to a matrix provided by Apple for icon sizes. Should I use these sizes strictly, consider them as a lower border not to go under, or consider them as a ceiling not to exceed?