First thing, let's google that studio! Lloyd Studio, Ltd. has been around since 1880... okay, that's narrowing our search a bit isn't it? Card colours were different front and back during 1880-1890... still good. 1880's were light card stocks.... still within that decade, good, good.
And that's it! Just like that, we've checked out four photographs and got a pretty good idea when they were taken. With more information on the subjects, we can narrow these dates down even more. And it really only takes one person in a group shot to make it easier to date the rest. Knowing Grandma's birthday and which one she is in this photo lets me pick out her mother (holding her), her father (behind), her half-brother from her father's first marriage (behind right), her half siblings from her mother's first marriage (boy and girl in front, right), brother (in the middle of half-siblings, front). Her Uncles, front left with two of her cousins. Her paternal grandmother, middle. Possible aunt behind grandmother. Just look how fast the picture gets identified!
Again, I'm no expert. And there are people who will, for a fee, find out when the photo was taken. But just look what we were able to accomplish on our own! That should give you at least some hope that you can do a lot of the leg work on your own. At the bottom here I've put the sources I've used to date these (and other) photos in my collections. Practice makes perfect so I always try to narrow dates on new photos as I come across them. One last note: Try to use as many sources for your references as possible. I'm a big fan of wikipedia; not for accuracy, but for the sources of their articles. ALWAYS check the source of your source if it's a blog or online community. Don't want someone blowing smoke up your kilt!
Dating a Photo