What does the share image generator make?
An image to post with your App Store link, or to use as your website's link preview. It shows your icon, the app's name, a tagline and a small line with the category and price, on one of four backgrounds. Turn screenshots on and the first one rises from the bottom of the card, the way a product page shows them; the Instagram size shows up to three.
Everything comes from your App Store listing, and you can change every line before you download.
Which size should I use?
Post and link preview (1200 × 630) for X, LinkedIn, Threads and Bluesky, and as the og:image on your app's website, so a shared link shows a proper card instead of a bare URL. It's the 1.91:1 shape most sites use for link previews.
Instagram (1080 × 1350) for a feed post. It's the tallest shape Instagram's feed allows, 4:5, so it takes up the most room on a phone.
Where does the tagline come from?
The first sentence of your App Store description, cut to fit. Apple doesn't publish your subtitle, so no outside tool can read it, but it's usually the better tagline: it's already short and it's what people see under your name in search. Paste it in.
Can I use it on launch day?
That's what it's for. Post the image with your App Store link on launch day, pin it to your profile, and use the same image on your website so every shared link looks the same. The X launch post guide has what to write next to it.
Can I add the Download on the App Store badge?
Not here. Apple asks for its badge to be used exactly as supplied, from its marketing resources, so the image says "on the App Store" in plain text instead. If you want the badge, add Apple's own file on top.
Does it store anything?
No. Your browser asks Apple's public lookup service for the app's details. The image is drawn on our server from what's in the form and sent straight back. Nothing is saved, on our side or anywhere else.
Use it for your own app: the icon and screenshots belong to the app's developer.