Hi,
InfoPath form attachments are indeed supported in a SharePoint form library --- you will not be able to promote them though. You can, however, upload the attachments to another library and return back just the link for it in your form. This link will be stored as a string which you can then promote as a column in your form library. Another benefit of this method is that your forms' sizes will be reduced because the attachments won't get stored in the XML itself.
You can do this with qRules - the command SaveToSharePoint allows you to save image and file attachments into a SharePoint library and/or a network location. I did a quick video tutorial on this - here's the YouTube link. You can try qRules for free - here's the download link.
Feel free to post here if you need assistance in using the tool.
Cheers!