Was it colour or b&w? Did it include any people or other distinguishing features. Was it dilapidated or still serving a useful purpose? Can you estimate the currency of the image? Did it seem like a print of a "famous" photograph or was it an original? Which hostel in which city/town do you remember?
I like a challenge, but sheds in Australia.. not exactly rare!!
Yep, it could have been anybody. I'd take a guess that it could have been Ken Duncan or Peter Lik, especially if it was colour, and especially if it was panoramic.