When choosing to upload from Dropbox, you may see a warning about granting the app access to your account.

This is perfectly safe.

The reason you get the warning is because not enough users using the integration with Dropbox and Img.vision yet. Out of precaution Dropbox shows the warning to visitors.

Rest assured, we will not abuse this access.

Dropbox warning on upload in Img.vision dashboard

You will also see this question:

Img.vision Dropbox question to allow access