There is considerable freedom over the appearance of text and images when making placemarks in Google Earth. Settings allow the control of text font, size, color, and style; paragraph alignment and line breaking; structured items including ordered and unordered lists, headings, quotes, and definitions; image inclusion from both local and remote sources, and several other "rich text" attributes.

The attached Google Earth KMZ placemark is a guide to these various options.

P.S. Remember that too much of a good thing can make your words look like a ransom note.