Their size is certainly too important. Consider thinking of reducing them with a utility such as Irfanview or Webresizer.
The confirmation by email contains a link which you should preserve in order to modify or delete your announcement. I f you didn’t preserve the link, we can send it to you by simple request. You also have the possibility to give us the number of your message so that we can delete it for [...]
You have just to click on “create a message” in the left menu of the home page and to fill out the formulary. It is useless to create an account in order to publish free announcements because you just need an email-address to valid the publication.