That was not at all how I envisioned him either. It took me a while to figure out who it was at first. Not the best drawing of sev.( just randomly popped into my head but I wonder what Snape would do if looked at his fanpop page. That would be interesting. ;)
I sort of laughed but have always thought that the illustrations were somewhat funny. JK Rowling's writing has a somewhat whimsical air. I always thought that the pictures, no matter how serious the situation in the book got, always exuded a touch of humor. So basically, yes, I did laugh, but I don't think it was strange. Although he does look slightly freaky.
Though a goatee might actually suit him. Not in the Alan Rickman version though, I could imagine him stroking his goatee while thinking. It would also give him more of a menacing look. The hair however...no, that's not Snape. I did laugh at the Spock ears :D
It didn't make me laugh. Since I started reading the books when the 3rd movie was coming out in theaters. I had a hard time envisioning Snape that way. I was already used to Rickman's Snape at that point. But, it didn't stop me from using Alan in my head anyway. LOL!