Anyone can make a post (TDO Mini Forms/Gravityform/ etc)

I’m working on a site that allows visitors to upload images that are automatically added to the blog as a post. Currently I’m using TDO mini forms but its not as slick as I’d ideally like it.

are there other plugins with the same functionality? I’ve heard you can do this with Gravity forms but ideally the plugin would be free.

thanks for any tips