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I've been told that a photo I took with an iPhone has a .png extension means that the photo has been altered or tampered with. I know I took the pic at that time.

Why are some of my photos in the .png format? Does it have anything to do with saving it in cloud? Any thoughts?

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    Joe - Some cameras record photos in the .png format natively. Even if you convert another file format to .png, that still does not necessarily mean you have altered the content of the image in any way. My guess is one of two things is going on here: Either the police are completely incompetent and don't have a clue that some images are recorded by modern devices as .png images OR they are trying to bluff you into admitting you altered the image. My money is on the second possibility. – Michael C May 31 '14 at 1:06
  • @MichaelClark - I made some edits to remove the legal-speculative angle, so it's back to the heart of what you're looking to answer. However, I would request that you avoid using comments to answer. Please use the editing and voting system as means to bring a question back, comments are very likely to be deleted, especially if they're used to replace answering. – John Cavan May 31 '14 at 1:20
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    @MichaelClark - Also, he mentioned it was with an iPhone. AFAIK, the native camera app does not save PNG. – John Cavan May 31 '14 at 1:22
  • But the basic question remains: Does converting from one format to another intrinsically mean a photo has been edited or altered? – Michael C May 31 '14 at 1:24
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    By that definition ALL digital photos are altered, since the RAW data readout from the sensor has been demosaiced and converted to JPEG, TIFF, etc. to be viewable. – Michael C May 31 '14 at 17:21
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The short answer is yes (unless you have a camera that can output PNG files (which, I believe, is very few)).

The long answer is (in general) sort of. As mentioned in the comments, file conversion is, technically, a form of alteration and so, for the vast majority of photos, having a .PNG extension means that they has been altered. This does not mean that the content of the photograph has been altered (at least, in a human sense), and not having a .PNG file extension does not mean that the file hasn't been edited. Your PNG files may still have some EXIF data that includes Capture date and time, camera model etc. that will allow you to determine and get some way to proving the actual time the photo was taken.

The conversion to PNG could come from where and how you are saving the files after the photos have been taken. For instance, some cloud services may automatically convert image files to PNG (maybe for compression, etc).

  • Just adding that it is possible for an iPhone camera app to save as PNG (see iosdevelopertips.com/data-file-management/…) although I didn't look to see if any offer that option. For the sake of proving a point you should be able to recreate the steps you used when taking the picture in question and you should wind up with another PNG. – James Snell Aug 2 '14 at 15:56
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If I take a photo with my iPhone 5s, the photo is a JPEG and approximately 700 - 2,000kb.

If I take a snapshot of that photo on the iPhone, the resulting image is a PNG and approximately 200 - 300kb.

(To take a snapshot I would view the photo, full screen, then press the Home and Power buttons simultaneously).

You can also install an EXIF viewer app - this will let you browse detailed info about photos, right on your phone. You could try the above - take a photo, then create a snapshot of it - and inspect with an EXIF viewer (or after transferring to a PC) to get an idea of how your phone manages images.

  • While this is all true, none of it seems to answer the question as to whether PNG implies the photo has been manipulated. – Philip Kendall Oct 28 '14 at 7:30
  • That's because it depends on your definition of manipulation. One person will say the photo has not been manipulated - if you looked at the two versions side by side they will look identical. However the file size is vastly different (and it's a 2nd copy), so clearly something has changed. Additionally, some of the earlier commentary implied there was a legal forensics issue and many replies offered information that third party software might convert the photo to PNG. I'm offering another explanation of how a PNG might be unwittingly created by a commonly used iphone feature - the screenshot. – youcantryreachingme Oct 29 '14 at 2:31
  • (and it offers possible answers for the last 3 questions - "Why are some of my photos in the .png format? Does it have anything to do with saving it in cloud? Any thoughts?" - as well as a suggestion for how to investigate their own photos further.) – youcantryreachingme Oct 29 '14 at 2:33

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