What does the script you are using to send the picture files look like? The code you include to attach the picture file likely contains a path variable where you may be able to test the value of the path to warn the user that no picture was found.
The script indeed includes a path variable (location where to find the picture (JPG) on the server).
E.g. I want to email a picture of itemnumber 12345
By script the itemnumber is filled in in a global field <GL_article>
In that case the path variable is filewin://server1/products/" & GL_article &".jpg"
It might occur that the picture of itemnumber 12345 is not available on the server
In that case I need a warning that the picture does not excist to avoid sending an email without an attachment.
In addition to this I would like to know which plugin i should use to send this email directly by Microsof Outlook without confirmation.
There are plug ins that list the contents of a specified directory. I'd be inclined to use such a plug in and check to see if "12345.jpg" is present in that list before attempting to send the email.
It's my understanding that FileMaker 11v3 can send email via MS Outlook without using a plug in. Not sure what you mean by "without confirmation".