Upload to Geograph Servers
This isn't a full submission process, but does allow reasonably easy upload of images direct from device.
Images uploaded via this process are then stored in your 'Temporally Upload Area' on geograph servers, can then proceed to submit them, either here on mobile, or even login on a desktop and submit them that with a big screen!
You can also select images from various online services. Also the 'Choose a local file' should prompt you to take a photo directly (at least on Android)(The 'auto' tickbox, will take you directly to v2 submission, so can submit it right away, without having to click though manually. Note only works if you have 'Save Location' enabled on device so the image as embedded GPS location!)