All illustrations where an identifiable human face is present require a model release. There are no exceptions. This includes illustrations based on photography or sketches of people as well as drawing from a real-life model. In some cases a release may be required even if the face is not identifiable. Please see the "Contextual Model Releases" section of this article for a complete explanation.
If the illustration is of a minor (a child under the age of 18), a model release must be signed by a parent or legal guardian.
If the illustration is of the artist (a self portrait), a model release is still required.
A model release must be uploaded with each file. If you're uploading successive illustrations based on the same model, the model release should be uploaded with each submission.
A valid witness signature must appear on the model release. Generally, it should be someone other than the illustrator.
Note: iStock does not accept digitally created or digitally signed model releases (this includes using script fonts as signatures, e-signatures and scanning signatures and then pasting into the model release).
Click here to download iStock's standard Model Release form.