The Image Preview Window
Select View Image from the Image menu (or press F7) to display an enlarged preview window. The preview window can remain on screen while more pictures are taken, making it useful for monitoring composition or focus in critical areas — for example, a model’s eyes during a portrait session.
The preview window is automatically updated when the image in the main window changes.
Scroll the image using the scroll bars, or click and drag with the left mouse button. If the preview window is open when a new picture is taken, it updates to show the same area of the new shot.
Image Types and Preview Size
When shooting JPEG images, the preview is the same size as the final image. To avoid a lengthy delay converting raw images, the embedded JPEG is displayed for cameras that shoot CRW raw files, or the associated JPEG when shooting in raw+JPEG mode with the EOS-1D and 1DS. The size of the embedded JPEG for Canon EOS 10D raw files is set using the RAW+JPEG custom function (CFn 8).