Hello Matt,
Thanks for submitting a question about user-submitted content. You may want to investigate user roles in WordPress. Providing certain privileged users with contributor status is the safest way to monitor incoming content. Unless you wanted a sort of open submission process, user roles is your best bet. The latter is possible but will likely require some custom coding.
WPForms also provides users with a File Upload form. This is another option available to you because BoldGrid comes with WPForms. Then, all you would need to do is display the uploaded images on a page of your choosing.
Best,
Christopher M.