When I began to try to recreate my ancestor's uniform and equipment, I didn't have so much as a photograph. I did however search and discover images of other soldiers from his regiment. I also found publically available copies of their correspondence, with occasional mentions of food and descriptions of uniforms and gear. Local newspapers from his regiment's home counties also had mentions of the arrival and distribution of rifles and uniforms. Sometimes information came from sister regiments raised nearby and during the same months.
You'll be amazed what is available in a simple Google search.