loadImage() -> saveImage() all metadata being stripped?

Programming Questions

nikpalmer

loadImage() -> saveImage() all metadata being stripped?

in Programming Questions • 2 years ago

Hi folks, if i load a jpeg image with metatdata, such as XMP or Exif, using loadImage and then save the image using saveImage it seems the original metadata is destroyed and replaced with a new more limited metadata. What i am doing is loading images from the net, showing them on screen, with the hope of also showing image meatadata such as Fstop, exposure, description, photographer etc. I guess i could use loadBytes -> saveBytes to bring the original image local then loadImage from the local file and skip the saveImage.

But it does seem odd that loading an image using loadImage() destroys part of that image, i would have thought that a primary image manipulation mantra was "be non-destructive".

Or maybe i am totally screwing it up?

kindest

nik

Replies(1)

PhiLho

Re: loadImage() -> saveImage() all metadata being stripped?

2 years ago

All loadImage does is to decode the image data, uncompress the pixels, to allow displaying it. Indeed, it doesn't care at all of metadata. When you do saveImage, you write the pixels (and only the pixels) in compressed form and the appropriate format.

Image manipulation is meant to alter an image... If you want non-destructive "manipulation", you need software copying the file, not the image itself. Just by uncompressing Jpeg, then recompressing it, you can introduce artifacts.

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