To give another deviant a direct link to this FAQ answer, use the following code in your comment or forum post:
How do I prove that I had permission to use someone's work?
For valid stock and resources you should document your source material, including direct links to the material where possible.
For works which were not originally stock resources you will need to provide the permissions statement or license granted by the proper owner by doing the following;
For your convenience we have provided a sample permissions document HERE but owners are free to word their permissions document however they see fit.
Note: please be certain to mention that a statement of permission is attached in your deviation description.
1. Convert the permissions agreement, email, note or other written text file of permission into a JPG, PNG or PDF file. This can be as easy as taking a screenshot of the text and saving it as one of the appropriate file types.
2. Start the submission process for your finished work and look for the small pencil icon to the upper right of the deviation thumbnail.
3. If your work has already been submitted browse to the deviation page of the newly submitted work and choose the option to Edit Deviation which is found in the column to the right of the image thumbnail.
4. Click on the pencil icon and choose Attach Permissions Document from the options.
5. Submit the permissions statement which you had previously converted to a JPG, PNG, or PDF format.
6. Save the changes or continue with the submission process.
The permissions statement will then be logged and attached to the submission. Only the appropriate staff members will be able to view this permission statement so you do not need to be concerned about private or personal information being revealed to the public.