KHpro can only display images with 10 colours or less, If you try and display a photographic image it will look fuzzy as it tries to convert all the colours down to 10 shades.
This is printed in the Manuel:
Image Types can be:
BMP, JPG, GIF, TIF and
PNG.
Image Size should be 288 pixels wide by 192 pixels high. Images for the Lyrics area must be 288px W by 96px H or smaller. Smaller images can be positioned on the display area in
several ways, including stretching to fit. Larger images are automatically scaled down to fit. Some loss of quality may be visible if the image size is reduced.
Image Colors
Images must be either 8-bits
(256 colors) or 4-bits
(16 colors) format, and should have 10 colors or less out of the 4,096 colors allowed in CDG songs. KHPro will not recognize 16-bit or 24-bit images at all. When a graphic image is imported into the Title Page, Lyrics or Credits Page, the colors are modified to the closest match of these 4,096 colors.
This is not a fault with Khpro but a limitation on CD+G format disc capabilities.