Render tune title, subtitle and composer in Latex/HTML and not in the image. This way the titles remains a constant size even if the image needs to be scaled. And we have that text appearance under our control. I can't find a way of switching off the tune title in abcm2ps, and have worked around by setting the title format to Y0. Y is not a defined ABC header and is not found in any Dottes tune.

X: 1
T: Old Tom of Oxford
M: C|
L: 1/4
K: Gmaj
B/c/ | "D" d e/f/ "G" g d | "D" c B A B/A/ | "G" G B/c/ d g | "D" f g a f/e/ |
       "D" d e/f/ "G" g d | "D" c B A e/f/ | "G" g d c B | "D" A B/A/ "G" G :|
z/A/ | "G" B d B d | "G" B d g/f/e/d/ | "C" c e c e | "C" c e g/f/e/d/ |
       "G" B d B c | "D" d e/f/ "G" g d | "G" g d c B | "D" A B/A/ "G" G :|