Can anyone help me on how to change the size of personal icons I've place on my dock? Some are smaller than others and I'd like to increase the size of those Icons. I've already resized the icons themselves in a separate program, but no matter the size of the icon they still display smaller than others.. Screenshot included. The Icon in particular in this screenshot is the small blue bird. I've enlarged the icon to 500x500px and the rest are the standard 256.. I just can't get it to display any bigger... Thanks in advance!!

Look at the same icon at the left, on the desktop. See how there 'seems' to be a size difference of that blue bird icon there too, in relation to all the other icons on the desktop?

The problem is not the size of the whole icon, but the fact that there is too much 'blank space' around the outer edges of the icon. You need to crop the edges of the image with a paint program.

This said, some images you simply cannot fix, as the image content is either much wider than higher (or vice-versa) - which seems to be the case - and icons need to be square. Cropping in those cases would also crop part of the image and not just blank space.