Smart rule on indexed items

Can I create a smart rule which will trigger whenever a new image file is added to a particular folder on my Mac (this folder is indexed in devonthink) and performs ocr the image ?

Will the ocr image also reside in the same folder ?

This is indeed possible. You have to restrict the search scope to the indexed group (see Search In popup), add the conditions Kind is PDF/PS and Word Count is 0. Finally, add the action OCR > Apply and ensure that the actions are performed On Import.