Does Helios allow users to upload the image if they do not have a URL where it already resides?
Helios utilizes TinyMCE as its WYSIWYG editor of choice and TinyMCE only supports inclusion of images already available online, by editing the HTML source of the event description to include an tag. Helios does not include an additional file upload utility so the only option for including images not already available online is to upload them to your site via FTP prior to including them in the event description.