There is a theory that LC had ASD, which certainly would explain to a great extent both the unusual inner logic of the Alice books (which always made perfect sense to my AS DD, for instance), and also his somewhat inappropriate conduct with young children.
Unless, of course, we just want to yell paedophile. It is a possibility. Certainly someone who behaved the way he did around children now could not be assumed to be doing so with honourable intentions.
But he lived in very different times. Both attitudes to sexuality and attitudes to children and childhood were very, very different to those we hold now. Also, eccentrics were far more tolerated and accepted, assuming they belonged to a privileged class.
In short, whilst I would have a serious problem with an adult male nowadays preffering the company of young girls, and wishing to take photographs of them naked for artistic reasons, I can actually see that an adult male with an out of the ordinary neurological setup could do so in that time and that place, with perfect innocence. Context is everything
Looking at it from another angle though, I can also see that if he was a paedophile in that place and that time, this would not have put him beyond the bounds of acceptable society, assuming he did not indulge his urges with respectable girls. There were plently of child prostitutes around for him to indulge himself with should he have wished to do so.
I do think though that, if it was known that his tastes ran that way (and it would have been), Alice Liddell's parents would have been far less accepting of the attention he paid their daughter.
Oh, and LOTR rocks.