Apple Macintosh PhotoFlash - Manual (Page 140)

Pixels and picas are units of measure used frequently by people who work
with images. A
pixel is a small dot of color. The shapes that appear on your
computer screen are made of pixels. If you set the unit of measure to Pixels,
PhotoFlash displays the horizontal and vertical dimensions of your image in
pixels, or dots. A
pica is one-sixth of an inch and is typically used to measure
blocks of text. If you set the unit of measure to Picas, PhotoFlash displays
the horizontal and vertical dimensions of your image in units of one-sixth of
an inch.
Note: While it is possible to specify different units of measurement for
horizontal and vertical dimensions, it’s usually preferable to use the same unit
for both.
If you plan to place images in a page layout program, you can define the
column size and gutter size used by PhotoFlash when it displays the width of
an image in “columns.”
For example, suppose you are creating a newsletter in a page layout program,
and the newsletter is formatted in three columns.
130 Appendix A
Column
Gutter