The app, called MindRDR, works through a second headset that the user wears alongside Google Glass, and communicates with the wearable device through Bluetooth.
It was created by London-based start-up This Place, which came up with the idea after using Glass, and finding that it could be more hands-free.
The headset, called the Neurosky EEG biosensor, uses a sensor that sits on your forehead and measures brainwaves. Concentrating triggers a higher brainwave reading, and this tells the app to take a picture, and then post it to Twitter.
Chloe Kirton, the company's creative director, said: "We started off by getting hold of Google Glass, which was really exciting for us - we really respect them and getting hold of one of their new products was really exciting.
"But when we started to use it we started to encounter what maybe you could call a usability issue; which is when you're swiping around looking for photos your arm can get a bit tired and we found ourselves holding our arms up and using the device, and we affectionately called this Glass elbow.
"So we wanted to task ourselves with finding a better way of using it, and not everyone has the high level of dexterity that is needed. The idea of mind control came up and we thought lets run with that and see where it can go. "
Google Glass only went on sale in the UK this month, having previously been available solely in the US, and comes with a £1,000 price tag. The headset puts a small display in the corner of the user's field of view so they can read messages as well as get news headlines from specially designed apps.
MindRDR is not an official Google app, with the technology giant confirming that the app has not been approved by them and will not be in available to download from the Glass app store.
"This particular application seems to work through a separate piece of kit which you attach to Glass," the company said in a statement.
Wearable technology is becoming increasingly popular with consumers, and earlier this week Amazon launched its own dedicated wearable tech store in the UK.
"While MindRDR's current capabilities are limited to taking and sharing an image, the possibilities of Google Glass telekinesis are vast. In the future, MindRDR could give those with conditions like locked-in syndrome, severe multiple sclerosis or quadriplegia the opportunity to interact with the wider world through wearable technology like Google Glass," said Ms Kirton.
"This Place is already in conversations with Professor Stephen Hawking, amongst others, about the possibilities MindRDR could bring as the product evolves."