Submission plugin like Tumblr's Submit page

Hi there, we’ve recently moved our site to WordPress, and we realised one thing.. We miss the Submit page on Tumblr, so we’re looking for alternatives for WordPress. For more of an understanding, the page we refer to as an example, is https://retrospekt.tumblr.com/submit

We’re looking at ways for external people to submit content to wordpress so we can just modify what needs modifying, with images, and away we go with the submissions.