With DJ-Classifieds, you can easily allow users to send attachments to advert author. This can be useful, for example, when there's a job offer, and the candidate wants to provide his CV. There are many other ways to use this feature, but I think this example is best.
First, you need to setup DJ-Classifieds to allow sending the attachments and decide what file formats you will allow being sent.
Go to Components -> DJ-Classifieds -> Options and open the Views tab and scroll down to Advert View section.
Here you'll find 3 options you need to set to get this feature working:
How it works
When all is set up, when the user uses the form to contact the advertiser, he'll be introduced with the option to attach a file.
This file, along with a message from the form, will be then sent by email to the advertiser.