Upload images from mobile

There is an option to do that but will require one manual step to make the images appear (that needs to be done from browser which can either be a mobile or desktop web browser).

There is an official app for WordPress that let you manage your website from a mobile app.

That mobile app will let you connect to your website and create post, pages, upload media etc.

You could create a gallery (using Dynamic Masonry Gallery Module, the second module of our Divi Gallery Extended plugin). Here you can assign the categories (of images) that you want to display in the module. Set up your gallery on desktop browser on your website.

In next step, you will only need to add images to the media gallery (using WordPress mobile app) without editing the page and assign them a category that is used by the module. 

However, the WordPress mobile app has no option to assign the images a category and you will have to log in to your WordPress website on browser and assign categories to your uploaded images so that they start to show up on the website.

You could download the mobile app and upload the images on the go and when get a chance, log in to web browser and just assign the images a category.