Change the font of figure captions

It can be done by loading the caption package and by choosing options or \captionsetup, for instance:

\usepackage[font={small,it}]{caption}

The caption package provides a lot more feature and is very well documented.

KOMA-Script provides commands for customizing fonts of certain elements:

• \setkomafont{element}{commands}
• \addtokomafont{element}{commands}
• \usekomafont{element}

The latter can be used for using the configured font for further elements. Among the supported elements are caption and captionlabel.

So here we could write:

\setkomafont{caption}{\footnotesize\itshape}
\setkomafont{captionlabel}{\usekomafont{caption}}

The memoir document class has this baked in. The provided functionality allows adjustments to the following parameters:

• The font commands used for the caption label (the Figure x: part).

• The delimiter that separates the label from the caption.

• The font commands used for the caption text that follows the label.

• The alignment/justification of the caption (left, right, hanging indent, etc)

And much more. See section 10.6 of the memoir manual for full details.

Memoir also includes support for things such as sub-captions and side-captions. Chapter 10 of the manual describes all this and much more.