Guide
How to add a gym membership card to Apple Wallet
Apple Wallet will not take a photo of a card. It takes a signed pass file, and a gym without its own app has no way to give you one. TapIn signs one for you, from the number on your card.
Why you cannot just add a picture
Everything in Apple Wallet is a .pkpass: a small zip holding the pass description, its images and a signature from a certificate Apple issued to the pass maker. Wallet refuses anything unsigned. That is what keeps a boarding pass from being forged, and it is also why most gyms never got around to it.
What the pass shows
The front carries the gym's name and logo, your name if you gave one, the member number, and the code itself, drawn large enough for a scanner. A pass with a strip image shows the colours of the logo across the top; a pass with your photo shows it as a thumbnail. Flip it over for the fine print and the link back to the gym's site.
Getting it on the lock screen
Open the pass in Wallet, tap the three dots, and turn on Suggest on Lock Screen. Wallet then surfaces the pass when you arrive at the location the pass names, if it has one, and at the time of day you usually check in. Double-clicking the side button brings Wallet up in any case, and the pass is one swipe away.
When the scanner will not read it
Turn the brightness up. Hold the phone flat, still and about ten centimetres from the window. If the desk uses a laser wand rather than a camera, it may never read a screen; the number is printed on the pass, so the desk can type it. If the number itself is wrong, make a new pass; it takes ten seconds and the old one can be deleted.