I have not once seen a formulae-as-images solution that I would consider acceptable, aesthetically. Common problems are:

- It almost impossible to align the baseline of the formula to the baseline of the surrounding text.

- Often, images are only used for "complex" formulae, while simple ones are implemented using normal typesetting. This resolves the baseline issue for simple formulae, but now the fonts between simple and complex formulae don't match. (This requires extra concentration for the reader, as in other contexts, different font styles are frequently used meaningfully.)

- The images often have sub-par resolution.