- Create a design at Instagram post size (or a 4:5 portrait size).
- Design the first slide, then click Duplicate on its thumbnail in the page strip so every slide keeps the same look.
- Change the text and pictures on each page. Drag thumbnails to reorder.
- Click Download, pick PNG and tick all pages. You get one picture per slide, in order.
Tip: put a small "1/5, 2/5…" counter and an arrow on each slide so people know to swipe.
For LinkedIn you can also download a PDF: LinkedIn shows a PDF as a swipeable document.