I believe there is a bug in the figimage handling when multiple images
are present. It looks like there is a negative sign in the
transformation that shouldn't be there. It is common to get upside
down in mpl, since bottom is 0 for us and usually bottom is top
Uncomment out the second figimage call to see the problem in the example below::
import numpy as np
import matplotlib.mathtext as mathtext
import matplotlib.pyplot as plt
parser = mathtext.MathTextParser("Bitmap")
parser.to_png('test2.png',
r'$\left[\left\lfloor\frac{5}{\frac{\left(3\right)}{4}}
y\right)\right]$', color='green', fontsize=14, dpi=100)
rgba1, depth1 = parser.to_rgba(r'IQ: $\sigma_i=15$', color='blue',
fontsize=20, dpi=200)
rgba2, depth2 = parser.to_rgba(r'some other string', color='red',
fontsize=20, dpi=200)
fig = plt.figure()
fig.figimage(rgba1.astype(float)/255., 100, 100)
#ig.figimage(rgba2.astype(float)/255., 100, 300)
plt.show()