Inserts a new thumbnail element(s) from an image to the specified index of the WebThumbnailsViewer control and specify the thumbnail text.
imageUrl
The image URL or image virtual path to which to add its page(s) as thumbnail(s). Each page will be added as a new thumbnail.
firstPage
The 1-based index of the first page to load.
lastPage
The 1-based index of the last page to load. Must be greater than or equal to firstPage. You can pass -1 to load from firstPage to the last page in the file.
thumbIndex
The 0-based index at which the new thumbnail element(s) should be inserted.
text
The thumbnail item text.
This example replaces the first thumbnail with a "image1.jpg" and set the thumbnail text.