Here is a formula which will display a preview of the image
IF(ToText([my file attachment field])<>"",
"<img src=" & URLRoot() & "up/" & Dbid () & "/a/r" & [Record ID#] & "/e6/v0' width='300' >")
)
Replace the e6 with e and the field ID# which has the file attachment.
Set either the width or the height parameter but don't use both.
Yes, mobile can easily upload pictures from your camera roll and I think also from taking a picture.
Juiced Exact Forms Plus is a great add n, but will not solve for this issue. it's purpose is to generate a PDF or Word document file attachment, although the generated document can also show images.