David doesn't like it. In fact, there is a thread here regarding that. I myself don't like the idea of images in sigs. But I do hope he will allow links in the sig.
You should have seen when Lord K had 13 lines lol. 5 is fine in my opinion. You can just about fit important system info into it, with an optional line for a quote or comment.
e.g.
Mobo
Processor
RAM
Graphics
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