smilies appear too high (in relation to text)

I would like to convert emoticons to graphics in my blog, but when I do, each emoticon graphic appears “superscripted” – ie it’s higher than the text surrounding it. This isn’t such a big deal at the end of a paragraph, but in the middle of a paragraph, it breaks the paragraph up because of the extra blank space required.

I’ve tried using different sets of smilies, including sets which work elsewhere (eg LiveJournal), but get the same result. I’ve also tried using different themes, but again, same thing.

Any idea why this is happening, and how it can be remedied?

TIA