iOS image sizes

[grandM]

So apple provides the possibility to add images for different devices using @2x, @3x. If however you are taking a picture with your iPhone and you want to show this picture on the screen afterwards should you save a @2x and @3x version of that image too? Or is it sufficient to make your first image large enough?

 

[PhoneyDeveloper]

There's no reason to use the @2x, @3x notation for images saved by the user of your app. Is that what you're asking?

It only makes sense for images shipped with your app. If you're planning on taking a photo and shipping it with your app then the answer is maybe. Using the 1x, 2x, and 3x images lets the device show an image that's specialized for the screen size and image resolution. You don't need to show an image that has pixels the user can't see. Also, app-thinning will strip out the non-used images. For an app-store app I'd say that it's a better idea to ship all three.

 

[grandM]

There's no reason to use the @2x, @3x notation for images saved by the user of your app. Is that what you're asking?

It only makes sense for images shipped with your app. If you're planning on taking a photo and shipping it with your app then the answer is maybe. Using the 1x, 2x, and 3x images lets the device show an image that's specialized for the screen size and image resolution. You don't need to show an image that has pixels the user can't see. Also, app-thinning will strip out the non-used images. For an app-store app I'd say that it's a better idea to ship all three.

The user can take a photo and save it. I guess it is not useful to save different sizes unless he switches from device.

 

[Mascots]

The user can take a photo and save it. I guess it is not useful to save different sizes unless he switches from device.

The effect is seemless for most iOS devices nowadays since its been awhile without one in production lacking retina - The image will look how it looks.

It's also backwards compatible with standard resolutions since the extra pixelage on images would just be ignored as with viewing a large image in a small space would.

Also, fun fact: when working with image resources in your app, use PDFs and scaled vectors in Xcode image sets so it does the work of creating the necessary 2x and 3x image versions for you.