Is it permissible to use images from the Internet—devoid of names or signatures—in design and to write on them, modify them, and republish them, adding the user's name to them, and is it permissible to post them on social media websites?

Modifying photographs of living beings is a matter of scholarly disagreement, with the preponderant view being that it is impermissible to modify or enhance them. As for photographs of inanimate objects, there is no objection to taking, modifying, or enhancing them. The basic principle is that the owner of the photograph has the right of innovation, and its use depends on their permission. However, placing a picture on the internet is considered implicit permission for its use, unless explicitly stated otherwise. Therefore, it is permissible to modify it under the mentioned conditions. It is permissible to write a name on the modified picture, provided that attribution is given to the owner of the original picture, and it is not permissible to give the impression that you were the original artist of the picture.