Instagram Carousel Downloader

What a carousel actually is (inside Instagram's head)

Instagram internally calls them "sidecars". The word doesn't show up anywhere in the UI, but if you've ever poked at the API response or read through someone's reverse-engineered scraper code, that's the name you'll see. A sidecar is one post (one shortcode, one URL) that contains up to 10 child media items.

Each child has its own media ID, its own CDN URL, its own resolution, its own format. They're not stitched together into a single file on Instagram's side. The app stitches them visually during playback — swipe right, render the next child, update the little dot indicator at the bottom.

Which is why our downloader presents them as N separate rows instead of one blob. That's how Instagram stores them; we're just surfacing that.

How to tell it's a carousel before pasting

In the feed, two tells give it away. A small stack-of-cards icon sits in the top-right corner of the post — four overlapping squares. Beneath the image, a row of tiny dots, one per slide. Either one means carousel.

Desktop post page is easier still. Arrow buttons appear on the left and right edges of the media when there's more than one slide. No arrows means single image.

A shared link on its own won't reveal it. The URL for a carousel is identical in shape to a single-image post — instagram.com/p/SHORTCODE/. No way to tell from the URL alone. Paste it here and the result page will show what's inside.

Slide order matches what you saw on Instagram

Photo 1 of N is whatever shows first when you open the post. Photo 2 of N is the second swipe. No surprises, no reordering on our end.

One subtle thing: if the creator edits the carousel after posting (removing a slide, reordering), Instagram updates the served content but keeps the same URL. If you saved that URL yesterday and re-paste it today, the slides you see might not match what you saw before. We fetch whatever Instagram is serving right now, not an archived version. There's no archived version to fetch.

Mixed photo-and-video carousels

Carousels can mix media types. A cooking post might have five photos and one 15-second video walk-through. A product launch might be all video. A travel post might be mostly photos with one video summary.

The result page handles this natively. Each row is labeled by type — "Photo 3 of 7", "Video 4 of 7" — and the video rows get the same merged-MP4-with-audio treatment as a single-video post. Our ffmpeg server does the merge. You don't notice the difference.

Consequence: mixed carousels take a few extra seconds to parse because we resolve each child's format independently. Normal. Not a hang.

Why the 10-slide cap, and what hits it

10 is Instagram's own limit. Always has been. Posting more than 10 images in one carousel isn't a feature anyone has — the app and API both refuse it. We don't add a cap of our own.

If you see a post with 10 slides, the creator hit the ceiling. Occasionally you'll spot them doing a "1/3" or "2/3" series — three separate carousel posts linked by caption — when 10 wasn't enough for the content. Each of those is a separate URL you paste separately.

Why 10 and not 20? Probably a mix of UX (nobody wants to swipe 20 slides), payload size, and some ancient internal decision from the early carousel days that nobody's had cause to change.

The cryptic filename thing (again, sorry)

Photo slides in the carousel save with Instagram's internal blob ID as the filename — same issue as single photos. Video slides save as instayolo-SHORTCODE-slideN.mp4, which is actually readable.

Reason is the same: Instagram's image CDN refuses any server-side request that tries to set a custom Content-Disposition, so your browser gets the file without a suggested name. Works fine for video because we proxy those; photos go via 302 redirect, which skips our naming step.

If you're downloading all 10 slides and plan to rename everything anyway, this is noise. If you're pulling a single specific photo, rename after download — a two-second click.