Not at the moment. Attachments (files, images, videos, documents) aren't supported in Askable's messaging.
Two workarounds
Send a link. Upload the file to a shareable drive or site (Google Drive, SharePoint, Dropbox or similar) and paste the link into your message. Check the sharing settings allow access for people outside your organisation.
Use email. You can find a participant's email address in their chat thread and send the file directly. See Where do I find a participant's email and phone number? Only use participant contact details for your research study.
