Keynote accepts all QuickTime-supported formats, including the following graphics file types:
TIFF
GIF
JPEG
PSD
EPS
PICT
Click Media in the toolbar, click Photos in the Media Browser, select the album where your picture is located, and then drag a thumbnail to position it where you want it.
The buttons at the top of the Media Browser give you access to images in your iPhoto library, movies in your Movies folder, or audio files in your iTunes library.
Choose Insert > Choose, select the file, and then click Insert.
Drag a file from the Finder.
Drag a file from another application.
After importing your image, you can drag it to position it wherever you want on the slide canvas. Drag the image to the slide navigator to create a new slide containing the image.
You can use the tools in Keynote to mask (crop) an image; change its brightness, contrast, and other image qualities; or erase its background.