it's necessary for covering all the bases for upload of image, modification (toning performed from the grading-server) and sending back the image (making it available online).
(if it covers a bit more it's for making sure there can be no legal complains)
This bit is worrisome:
When you upload or otherwise submit content to our Services, you give Us (and those we work with) a worldwide license to use, host, store, reproduce, modify, create derivative works, such as those resulting from translations, adaptations or other changes we make, communicate, publish, publicly perform, publicly display and distribute such content. This license continues even if you stop using our Services. Make sure you have the necessary rights to grant us this license for any content that you submit to our Services.
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