Back in the day I used TheDraw for fine editing. It was a DOS program.
(It's been over 20 years since I last used it, so I don't know where to start other than saying you'll probably need to use DOSBOX to run it.
I also used a graphical program for starting with long ANSIs that basically used the half-character blocks to start with basic pixels, but I don't remember the name. (Basically, the characters that turn 80x25 text into 80x50 pixels.)