I have bought a lot of guitars & basses online, both new and secondhand and so far I've not had a bad experience in buying new instruments with just the stock pics shown, however when I bought my GuitarGuitar exclusive AAA Gibson Les Paul standard, GuitarGuitar listed photos of each guitar, so I had a choice of over a dozen and knew exactly what I was getting visually as well as knowing the weight (I chose the lightest one, which also was the one with the best figuring). Just to be sure it wasn't a dead lump of porridge (it isn't) and as I am lucky enough to live a few miles from the Epsom branch, I was able to have it delivered there so I could check it over very carefully before accepting it.
Come to think of it, I believe most of my other instruments with a natural or sunburst finish have been bought secondhand so I was able to see pics of the woodgrain before buying. My Ben Gibbard mustang is a good example of this, it has really nice grain in the Ash where the joins between pieces are not very obvious, whereas I've also seen examples with mismatched and/or ugly grain, which I'd not have been happy with if I'd bought unseen.