After far too long, I finally launched support for importing multi-photos from Instagram via OwnYourGram!
I had to make a couple tough calls, which I'm not entirely happy about, but I think it's an acceptable compromise for now. The main limitation of the way it currently works is that Instagram posts that mix photos and videos in the same post will import the videos as just their poster frame. Additionally, you can tag people in the individual images on Instagram, but when that's converted to a Micropub request and sent to your site, the person tags are combined into one list associated with the main post.
The reason for doing it this way is there were already several websites and Micropub implementations that support the "multi-photo" concept, but very few that support "collections." The difference is a multi-photo is a single h-entry that has multiple photo URLs, whereas a collection is an h-entry that contains multiple h-entrys inside of it. The collection concept allows a much richer representation of things, since you can have a collection containing photos, videos, or anything really, and each h-entry within the collection can have its own tags, person-tags, etc. There are some more notes on the advantages and limitations of each on the IndieWeb wiki.
But right now, there are very few implementations of collections at all, and as far as I know, nobody's Micropub endpoint supports creating collections anyway. In contrast, there are several examples of multi-photos along with support in Micropub endpoints, including recent support for it in micro.blog. So that's a compelling argument for making OwnYourGram support the simple case first, and eventually I'll see about adding support for full collections later.
Since not everyone's site supports multi-photos, I decided that for all existing OwnYourGram users, I would maintain the existing behavior where it only posts the first photo to your site. This way I avoid surprising people with a new kind of Micropub request. If you're an existing user and want to accept multi-photos, then you just need to be prepared for the "photo" property to be an array, and you can enable multi-photo support in the settings. New users will have this enabled by default.
I talked about this upcoming change on episode 1 of my new microcast "Percolator," so please subscribe if you're interested in following along with other developments I'm thinking about!
Looking forward to seeing some multi-photos on all your websites!