I prepared a web frontend for Tesseract OCR to do optical character recognition for Malayalam - https://ocr.smc.org.in
You can use images with English or Malayalam content. Use the editor and the spellchecker for proofreading the text recognized.
Your image does not leave your browser since the recognition is done in browser and does not use any remote servers.
Source code: https://gitlab.com/smc/tesseract-ocr-web