Per the rules (see below), your submission - in its entirety - must be owned by you/your team. So if you have the rights to use the pictures with branding or logos you may do so, however, you must comply with any licensing requirements from the brand you're using.
(viii) Intellectual Property: Your Submission (including all design elements, functionality, and program code) must: (a) be your (or your Team, Small Organization, or Large Organization’s) original work product; (b) be solely owned by you, your Team, your Small Organization, or your Large Organization with no other person or entity having any right or interest in it; (c) not violate the intellectual property rights or other rights including but not limited to copyright, trademark, patent, contract, and/or privacy rights, of any other person or entity; and (d) be publicly available and open source under MIT license. A Maker may contract with a third party for technical assistance to create the Submission provided the Submission components are solely the Maker’s work product and the result of the Maker’s ideas and creativity, and the Maker owns all rights to them. A Maker may submit a Submission that includes the use of open source software, provided the Maker complies with applicable open source licenses and, as part of the Submission, creates software that enhances and builds upon the features and functionality included in the underlying open source product. By entering the Hackathon you represent, warrant, and agree that your Submission meets these requirements.