Looking specifically at:

>I can get the value using
>
>lcValue = evaluate(ImageSource)
>
>But what should I do with this value now? How can I copy that value into the file?

Is this what you are looking for?

STRTOFILE(m.lcValue, m.cOFile)

>
>Also, how can I check if the format of my ImageSource is still TableName.ColumnName or it's something more complex like that extra function?

By checking for the presence of parenthesis inside ImageSource?