Easy! If you're a member of the group, add your photo to the group pool. (If not, join the group, because only group members can contribute to the group pool.)
The easiest way add a photo to a group is to go to the photo's page and click the "Send to Group" button between the photo title and the photo. Then choose the group you want to send it to, and you're done!
Only you and the group administrators can remove a photo from a group pool.
Note: If you share a photo that you marked as private with a group you are a member of, it's as if other group members have full access to that photo. They can add comments, notes, and tags. The photo isn't displayed for people who aren't members of the group.
If you have a free Flickr account, you can add any one photo to a maximum of 10 group pools.
If you have a Flickr Pro account, you can add any one photo to 60 groups.
Some free account holders might have added a photo to more than 10 group pools. If this is you and you want to add that photo to another group pool, you have to do a bit of housekeeping first because you're over the limit. To do this, open the photo page and click the [x] next to the group name on the right to remove it from that group. When you're within the limit, you can add that photo to a group.
Click a photo you want to add to a discussion and then click "All Sizes" if it is available above the photo. Choose the size you want. (Most people recommend Small so that the post you add it to won't take a long time to download.)
Scroll down to the HTML code near the bottom of the page, right-click on that box and select Copy from the shortcut menu. Go to where you want to paste the photo into the discussion post, right-click, and select Paste. (Thanks Chrisser.)
Public groups are listed around the site and on the groups page, profiles, and photo pages if the photo is in a group pool.
There are two types of public groups: anyone can join and invitation only. Group administrators can choose to show or hide the group photo pool and discussion topics at any time.
Private groups are not listed anywhere on the Flickr site. You can join them only by invitation.
If you are an administrator, go to your Groups page and select the group. Select Administration on the right. Go to Privacy toward the bottom. Click "Make this group private."
You can make a public group private, but a private group cannot be made public.
When you create a group, you are automatically made its first administrator. As administrator, you can also promote members to help you run the group. You can promote your members to either moderator or administrator status.
A group admin can:
There's no limit on the number of admins a group can have, although you should be aware that once someone becomes an admin, they can never be demoted.
Though there is no limit on the number of admins, we suggest you limit it to those you feel you can trust to maintain the integrity of the group because of the tools available to change group features. Flickr staff won't step in and remove people from your group if someone is abusing their admin privileges.
A group moderator can:
You can read about keeping your group happy on the Tips for Running Your Group page.
Adding a photo to a group pool allows any group member to view your photo and add notes, tags, and comments, regardless of the photo's privacy setting.
Your photo retains the privacy settings you set for anyone who isn't a group member. It also stays in your photostream, available to everyone who can view it. You (or a group administrator) can remove your photo from the pool at any time.
Go to your Groups page and select the group you'd like to leave. On the right-hand side, underneath the box where you can search group discussions, there's a red link labelled 'Quit (group name)?' Click this and you'll be taken to a page where you can leave the group.
The only way to delete a group is to leave the group as the last remaining member. But you can quit the group (described above).
A group can't be deleted if it has more than one member.
We’ve built a new feature to give group administrators more control over the sorts of content they will allow in their pool. If you run a group, you can say “I only want safe, geotagged video in my pool” by choosing from media type, safety level, and whether something is geotagged. There’s more info about this in this Groups FAQ.
Because of these new tools you may get an error when trying to add a photo or video to a group pool. If you get this error, check the group rules against the content you’re trying to add.