The html code for adding a IMG file to a page is different from adding a Flash file.
If your script is trying to add Flash to a page using IMG SRC tags, it plain won't work.
You'll have to do some sort of if statement, with the appropriate html. To get the html tags for a flash file, you can use the HTML files that Flash generates (if you have html selected as one of the export types). Open 'em up in notepad and look for everything inside the OBJECT tags.
Then make a statement that either displays a jpg/gif using IMG SRC, or a flash file as OBJECT.