The following ideas will help increase your interactions during and after an event and also help you with ideas for creating content. First...
Do your homework
Make sure you have all the relevant social media links for the event. There may be an official hashtag, or event page, also remember to seek out the event organisers social media pages. These are the places you are most likely going to find photography from the day.
Don’t miss your window of opportunity for engagement
When you've found the event photography take a look through, and get tagging yourself and others you recognise in the photographs. Comment on relevant posts and do your best to continue conversations shared at the event. Keep engaging with the event content to boost your presence. Remember being ‘social’ is what social media is all about. Don’t be sell-y though, it's off putting. Also remember part of why you came to an event was to make connections and network and that’s best done by being friendly. Interacting with the event photographs and content is a great way of doing that.
If you can’t find a photo of you or someone you know then look for speaker photographs and make a friendly comment about their talk or ask a question. Be interested in what other people are asking too, this is your chance to make new connections.
Create a blog or post using a photograph for attention
Of course you could use your own snaps, from the event, selfies are great for immediate posts or for use in Stories. But maybe when you add them to your blog or post you'll feel a more professional shot might improve it or perhaps you missed photographing something you'd like to mention. Go back to the posts you’ve interacted on and find photographs you think would work well for your content (see tip 3 for copyright advice).
Look for more generic photographs like the food, goody bags the room layout, etc for alternative ways to illustrate your content. You could create an anecdote about something you heard or saw or just reflect on some of the great conversations you had.
The copyright for photographs is owned by the person who took the photograph unless sold under contract
It's a common misconception that photographs used in a public arena are open for all to use freely. This is not the case and here is my suggestion for borrowing an image from someone else, in an ethical and fair way. This applies whether they are a professional, amateur or candid photographer. How about dropping the photographer a quick message and ask them would they mind you using one of the pics you’ve seen for your blog, post, etc? For one-off uses like this, a friendly "Hello, I’d like to use it here, etc’ could possibly be agreed in exchange for a photo credit. You may also find the photographer would like to feature your blog or post and share it for you as you’ve chosen to use one of their photographs. High profile events, celebrity speakers or printed use of images are likely to incur a charge. Best just to ask.
An alternative to seeking permission would be to share the original post which features the photographs you are interested in, this way the link to the original photographer is maintained.
Have fun with your photographs and if you take a pic of me at an event I'd love you to tag me in as Catherine Berry or Entirely Catherine Photography.