Returns a thumbnail image of the content in a container field, according to a specified height and width.
field - any text, number, date, time, timestamp, or container field; or any text expression or numeric expression.
width - the width for the thumbnail.
height - the height for the thumbnail.
Data type returned 
Originated in 
FileMaker Pro 12.0
Returns an image that’s stored in a container field according to specified values for width and height. The thumbnail image always maintains the proportions of the original image.
Note  If the field parameter does not specify a field that contains image data, field must evaluate to the file path of an image. See Creating file paths.
Example 1 
Exports a thumbnail with a maximum height and width of 50 points.
Set Field [Invoices::ExportContainer ; GetThumbnail ( Invoices::Container ; 50 ; 50 )
Export Field Contents [Invoices::ExportContainer]
Example 2 
Creates a thumbnail, exports it, and attaches it to an email.
Set Field [Invoices::ExportContainer; GetThumbnail ( Invoices::Container ; 50 ; 50 )
Set Variable [$ATTACHMENT; Value:Get ( TemporaryPath ) & GetContainerAttribute ( Invoices::ExportContainer ; "filename" )]
Export Field Contents [Invoices::ExportContainer; "$ATTACHMENT"]
Send Mail [Send via E-mail Client; To: Customers::Email; "$ATTACHMENT"]
Related topics 
Functions reference (category list)
Functions reference (alphabetical list)
About formulas
About functions
Defining calculation fields
Using operators in formulas