@DLoman I presume that you've upgraded to Vegas Pro 18 since you've posted on the Vegas Pro section. If you have, you can insert a slideshow as follows :-
Click 'Insert' then 'Slideshow' to open up the Slideshow Creator dialog. Click 'Add Pictures' Select the images you want to include using the Explorer window that appears Arrange the images to suit using the icons. Click 'Settings' and change the parameters to suit. Click 'Create'. Close the dialog.
Thank you for your post. Movie Studio 18 is not a VEGAS product and support for it is not available on this site. However, support for Movie Studio 18 is available from the MAGIX user forum https://www.magix.info/us/video-forum/movie-edit-pro/