Delta2D Consumable: Why does Delta2D seem to forget sometimes that an image is already activated?

Activation information of images is saved in two places: on DECODONs Consumable Server and on your filesystem: in the pool, where the activated images were located at the time of their activation. This means:

• If you create another project in the same pool, and reuse images that are already activated, everything is supposed to be transparent, you should instantly be able to use the images in every aspect. Activation information for these images is already existing in the pool.
• If you export a project with activated images into a new pool using Delta2D's export function, the activation information should be exported along with the images and should be present in the new pool as well.

On the other hand, that means as well:

• If you open a different pool, or create a new one, and import images again, which you already activated in another pool before, these are completely new images for Delta2D at first. Why? In the new pool there is no activation information regarding to these images. You need to activate these images again to create the activation info in the new pool as well.
  BUT:
  Since DECODON's Consumable Server already knows these images, re-activation is free.
  
  IMPORTANT: if you do these steps and re import already activated images into a new pool, please make sure to import them exactly with the same preprocessing steps as you did before you activated them: rotate, flip, invert, and despeckle with the exact same parameters, and to repeat the activation with the same account it was done before.

Technical Background

Delta2D does not recognize images like a human, like "ah, this is the image he scanned the other day and saved it with this name there and there". Delta2D calculates universally unique fingerprints of every image to determine the identity of an image. If two images have the same fingerprint, they have the identical contents, i.e. they ARE identical. Regardless of what their name is, where they come from, etc. And vice versa: if only one pixel differs between two images, they ARE different. Even if one is a modified copy of the other image.
And since in a new pool there is no activation info matching to the imported image, Delta2D needs to contact the Consumable Server to (re-) create the activation info and write it down in the new pool. Already activated images are never charged again in the same account.