By default UDO expects that you want to display GIFs (see above). But it is possible to display any other kind of image format, too.
To tell UDO which suffix you want to use the next time you use the !image command you can use the command !html_img_suffix.
If the upper tiger isn't inside a GIF but inside a JPEG image you can insert the following command right before the !image command:
!html_img_suffix jpg
If the file is named tiger.jpeg instead of tiger.jpg use the following line:
!html_img_suffix jpeg
The setting is used for all following images. If you want to display a GIF next time you have to use !html_img_suffix gif before the next !image command is used.