I don't like images in signatures at all, especially as they're not regulated as to size. As a result, I've had signatures disabled for quite a while. I don't need a signature taking up 5 times more space than the post itself, it's frustrating to weed through the thread looking for posts obscured by massive signatures.
Having said that, I do find I'm missing out on messages in people's signatures.
Avatars do a nice enough job of showing personality, I don't think it's necessary to have both a generous sized avatar and an unlimited sized signature. Most internet forums that I've seen have images in sigs disabled. And the avatars can be quite big in size too, I've seen one on this forum which is 400k!
I say text only signatures, or at the very most 100px tall images.
p.s. I realise the irony of having an image in my signature, but you'll notice it's only 100px tall because I don't like to clog up your screen either

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