Is there a way for me to use SimpleViewer Pro to show a large amount of text with the pictures presented
There is technically no limit to the amount of text you can display for each image (although real-world constraints such as the size of the user's browser window will effectively provide a realistic upper limit).
If necessary, you could increase the captionHeight (in svBuilder-Pro's 'Customize -> Caption' section) to accommodate larger captions.
You could also choose to display your captions in an area other than the default position below the thumbnails using the captionPosition configuration option.
For possible values of captionPosition, please see its description in the Caption Options section of the Config Options page.
or to have the text in the HTML page change when clicking on a thumbnail in the SimpleViewer Pro to present the main image
SimpleViewer Support Team.