How come some icons can be GIGANTIC in a panel in gnome while others are restricted to being TINY.?

How come some icons can be GIGANTIC in a panel in gnome while others are
restricted to being TINY.?

If you create a new panel in GNOME desktop
assuming that you added it to the left or the right

assuming that you modified it so that it has a width of 200px or more.
if you right click on it and select
Add to Panel...
most things you add are tiny, most icons of new things you add are tiny,
trash bin is tiny, internet is tiny, but if you add
Swimming Fish
Brightness Applet
etc..
they are not tiny.
they are like 100%, huge.
how is this possible?
my icons are currently being smallerized by the panel and i do not know
how to give them more space.
i created an icon that reads
RESTART APACHE
but the icon is tinyized by the panel.
it has been smallerized to the point that it looks squeezed.
what is it that this FISH and other apps got that do not seem to auto
squeeze their icons when added to the panel?
i need to know so i can copy such settings for my own icons.