Why image metadata is stripped on transformation?

When images are involved, there is a lot of other types of data embedded in image files that can add unique semantic information to the images and are hardly ever used.

When the image is uploaded to Cloudinary without any transformations, image meta-data is kept as is, untouched.

Cloudinary strips off meta-data when transformations are applied to reduce storage and deliver images faster. Cloudinary generally strips ICC profile, EXIF-data, IPTC information etc on transformation. You can keep the metadata during transformation by using the "keep_iptc" flag - 

http://res.cloudinary.com/demo/image/upload/fl_keep_iptc,w_500,h_500/test%20-%20folder/animals/exif_sample.jpg

If you want to strip the metadata on upload, you can use an incoming transformation.

More about incoming transformation here: https://cloudinary.com/documentation/upload_images#incoming_transformations