Strange *.BMP show in the web *.JPG don't

I found something strange. I try to show an Image in the web. Here is the formular

“<IMG SRC="” + @LowerCase(“/”+@ReplaceSubstring(@Subset(@DbName;-1);“\”;“/”))+

“/IDS/”+ @Text(@DocumentUniqueID)+

“/$FILE/” + @AttachmentNames + “?OpenElement">”

It works with *.BMP images but not with *.JPG

any ideas?

Michael