yes and no, as always with any fandom you have the group of fans who will make and post the lude/pornographic images of a character, this includes MLP. The brony community in general is fine as long as you stay within the safe areas of the internet.
Googling ponies in general is fine but you have to be aware that some sites will lead to the pornographic part of the fandom, which again can be said about all fandoms, so it's best to keep an eye out on what your daughter is clicking on (as you should be doing anyways as a responsible parent).
Deviant art isn't terrible either, the ration of appropriate to inappropriate pictures is good, but once again just keep an eye out.
Youtube is a place you may want to be wary of, while there won't be any porn on youtube, there is still a fair amount of adult oriented material including violence or socially acceptable unbehavior of MLP on youtube, so i suggest picking out content from there yourself and showing it to your daughter, start out with this maybe http://www.youtube.com/watch?v=jW5n3k2VgZE
If i had to point out the safest place to look up My Little Pony material, i would have to say to stick to equestriadaily.com as they post positive content such as well made fan art, music, news about the show, and games and in general the people there are nice, or at the very least not outright volatile.