Hi Meg
Your photo is Pre 1871, after approximately that date James Hertz put the property number on his photos. The square corners also indicate it is early. He operated from Lumb Lane from 1865 possibly a bit earlier until his death in Jan 1873. His wife then took over and continued the business but from 5/7 Lumb Lane.
James had opened a new studio at no 5 in about May 1871 and was advertising this address on the photos.
Hope this helps
Steve