Apple Macintosh PhotoFlash - Manual (Page 135)

The thumbnail settings appear in the lower-left corner of the Preferences
dialog box.
Small thumbnails are 80 x 80 pixels and large thumbnails are 128 x 128
pixels; both use millions of colors and medium-quality JPEG compression.
Small is the default setting and produces the best results in catalogs. You may
want to change the settings if you’re planning to use your images with other
programs that display large thumbnails.
If you have special needs, you can use the Custom setting to define the exact
size, number of colors, and compression settings that are applied to the
thumbnail stored with the image file.
You can set the size of custom thumbnails up to 512 x 512 pixels.
You can also set the number of colors that custom thumbnails use. The
greater the number of colors, the more disk space the thumbnails use. If you
choose millions of colors, you can choose a level of JPEG compression to
reduce the amount of disk space required for each thumbnail. High quality
means a small amount of compression, but the thumbnail image will be of the
highest quality. Low quality means a high level of compression with a
corresponding loss of quality.
These settings are dimmed until you
click the Custom radio button.
125 Setting PhotoFlash Preferences
Click here to change
the size of saved
thumbnails.
Choose the compression used for custom
thumbnails from this pop-up menu (available for
millions of colors only).
Choose the number
of colors used for
custom thumbnails
from this pop-up
menu.
Type a custom size for saved thumbnails here.