all I icons like that will be roughly the same size. Each screen has 16 "spaces" to place icons in a 4x4 grid. Some widgets take up two or three of these spaces, but icons for apps, shortcuts, and folders only use one, and they cannot be bigger than one space. Some home replacement apps out there may allow you to edit the number of spaces, but the go the opposite way you are think. that try to cram more icons into that space.