Using Automator and AppleScript to replace text in an image
Acorn 5.4+ includes a scripting interface for replacing editable text in your image.
For Applescript:
tell application "Acorn"
tell document 1
replace text "$foo$" with "This Is The New String"
end tell
end tell
For Javascript:
doc.replaceOccurrencesOfString_withString("$foo$", "This Is The New String");
Combine this feature with pre-made templates and you can automate the making of templates, guest tags, or anything else that combines lists of text with images. See below for an example that starts with a simple template. Applescript drives the text replacement along with saving the images as PDF.
set priceList to ["$4.99", "$9.99", "$3.99"]
set itemList to ["Eggs", "Pizza", "Cheese"]
repeat with i from 1 to number of items in priceList
set price to item i of priceList
set title to item i of itemList
tell application "Acorn"
set doc to open "/Users/gus/Desktop/Coupon Template.acorn"
tell doc
replace text "$title$" with title
replace text "$price$" with price
set fileName to title & ".pdf"
web export in "/tmp/" & fileName as PDF
close without saving
end tell
end tell
end repeat