Usage of "in figure" vs. "on figure"

I saw both versions ("in figure" and "on figure"), however---what is more correct? And is there any difference?

EDIT: In scientific papers, standards and other publications, "figures" can be found. They are also denoted as "pictures" sometimes (informally). When someone wants to refer to a part of a figure, he or she can write either "in figure" or "on figure". I am interested in figuring out if there is any difference in these two cases.

The standard is "in". From a random article on my desk:

...and isoamyl alcohol designated in Figure 2 were used...

Figures, as graphical elements, use the same terminology as other graphical items: in a painting, in a photograph, in your web browser.

Incidentally, even more common is to not use "in" (or "on") at all:

...did not migrate to 0.03 M sodium chloride (Fig. 2A, right).