I have several maths formula images generated by latex2html, the images are transparent gifs.

I want to use these images on a webpage with black background, so I inverted the color, so all the images are now displayed as white on my black background.

The problem is: I have used a different color - light blue - as the color of the text, and I want the maths formula to have the same color as the text. Does anyone know how to achieve such color change?