In absence of that facility, here is an AppleScript (if you are on Mac) that exports the PDFs from the selected notes, retains only the scribble layer (discards the template), converts that layer into PNGs and then appends those PNGs at the end of the original notes:
Code:
tell application "Evernote"
set thePath to path to temporary items
set thePath to the POSIX path of thePath
set thePath to thePath & "ever"
set theSelection to get selection
repeat with theNote in theSelection
set theSelecList to {theNote}
export theSelecList to thePath format HTML
do shell script "cd " & thePath & "; /usr/local/bin/pdfimages -p -png *.resources/*.pdf ever; /usr/local/bin/mogrify -negate *.png"
set theImages to do shell script "cd " & thePath & "; for i in $(/bin/ls *.png | /usr/bin/cut -d '-' -f 2 | /usr/bin/uniq); do /bin/ls ever-$i-*.png | /usr/bin/tail -n 1; done | /usr/bin/tr '
' ',' | /usr/bin/sed 's/.$//'"
set AppleScript's text item delimiters to ","
set the imageList to every text item of the theImages
set AppleScript's text item delimiters to ""
repeat with theImage in imageList
append theNote attachment thePath & "/" & theImage
end repeat
end repeat
do shell script "rm -rf " & thePath
end tell
Btw, you need Poppler and ImageMagick for the script to run.