Corrupted files after changing extension

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tedis2010 Author

Level 1

4 points

Corrupted files after changing extension

Hello,

I've been working with files for a long time and usually my routine is to change extension(file type) for thousands of the files. I've been doing JPEG to PNG conversion all the time by simply replacing ending (i.e. test.jpg to test.png) and it always worked since last week. Now when I rename files to .png - in finder it shows that it is PNG Image, but when I upload it anywhere online - it is still being detected as .JPEG which wasn't happening before. Any clues ????

iMac 27″, macOS 10.15

Posted on Apr 12, 2021 11:35 AM

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Answer 1

HWTech

Level 9

60,650 points

Apr 17, 2021 1:26 PM in response to tedis2010

Changing the file extension does not change the file type or contents of the file itself unless perhaps you have some automated process setup for converting the contents of those .jpg files to .png image format. Changing a file extension with any OS just changes the file extension and does not change the internal data of the file. If you want to convert a .jpg image file to an actual .png image file, then you need to use an app to perform the actual image conversion. To be more clear changing the .jpg extension to .png does not change the image format of the file so the image file will still be in a .jpg format unless you use an app to convert the file. Some apps and operating systems just look at the file extension to determine file type while other operating systems and apps will actually look at the meta data within the file to determine the type of file.

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