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Editorial Team
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Asked: 2026-06-02T07:30:15+00:00

I am in the process of testing my iOS application, everything goes smoothly on

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I am in the process of testing my iOS application, everything goes smoothly on the iOS Simulator (of course), but when I test on the Physical Device, some strange things start happening.

I have an image inside of a UIImageView, and I am using it as the pop-over background. When I run the app on the device, it appears as a black and white striped image.

There are no errors, no warnings, no memory problems (as far as I know), and nothing ever shows up in the Debug windows.

This is the image that appears:
White/Black striped popover

My original image is mainly of a dark grey tone with pattern. It is saved as a PNG and is copied into my project. It’s even under source control. What makes it even stranger is that when I change the image to something completely different, it works.

I’ve renamed, re-imported, etc. Nothing seems to work.

Any ideas? Where is this white/black image coming from? How can I fix this?

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1 Answer

  1. Editorial Team

    The PNG your application loads is not a byte-for-byte copy of the PNG you added to the application bundle. XCode makes some changes to it, putting the channels in BGR order and messing with the alpha. See this post on iPhone “Optimized” PNGs.

    This is speculation, but some property of your image – the channel order, bit depth, alpha, or similar – may not be what XCode assumes. Then it would end up swapping channel values it shouldn’t, corrupting the image. (If your image is grayscale, with one channel, that alone shouldn’t be the problem, however.)

    Try creating a new, blank image in the same size as your original, then copy the contents of your background image into the new one. If your image is opaque, make sure it has no alpha channel.

    You might also like to open your problem image in Preview, and select ‘View’ -> ‘Show Inspector’. I’ve attached the sort of information I see on images that do work.

    Preview Inspector showing General tab

    Preview Inspector showing PNG tab

    Edit: it is possible to prevent XCode altering your files. In your ‘Build Settings’, under ‘Packaging’, there is the option to ‘Compress PNG Files’. Switch this off if you need the PNG files in your project duplicated exactly. Your app will take more time to load images, but you may be able to compress your PNG files into smaller sizes. See Xcode’s built-in (de)optimization.

    enter image description here

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