The striking images on these cards date from 4/19/1906, day 2 of the fire. Most look southeast from Lafayette Park past the corner of Gough/Sacramento toward Polk Gulch and Nob Hill. 1905 Sanborn (V. 3 sheet 260) shows details of the area before the fire. Kennedy's fire timeline describes the progress of the fire in detail; it crossed Van Ness but was stopped at Franklin at around 3 AM on 4/20/1906 (day 3). Punnett's Two Years After map shows that the fire burned to within a block of the park. Doolittle shows the burned area after the fire, looking east across Van Ness between Bush/Pine toward Nob Hill.
These postcards all show the same view; a higher resolution image is here. Later on day 2, a large tent has been erected, the park is filling with refugees and their belongings, and the fire is much closer. The houses at 1812/1814 Gough again appear at the right edge. Just left of the woman's white blouse is 1919 Sacramento, still standing in 2020.
Steve's SF postcard pages: