Just a brief summary of my thoughts on this. Photographs taken with a DSLR camera are excellent for marketing purposes. They exhibit the correct hue of the stones in an ideal setting (lighting and background). This is probably why I continue to use them on our social media platforms. Additionally, it allows a professional aspect that simple phone photos do not.
However, phone photos have the distinct advantage of being able to be used directly to sell to customers. Gemstones in your hand exhibit the correct colors in a different environment and are more likely to be exactly what the naked eye sees (DSLR cameras often show far too many tiny details from the macro lens that the naked eye cannot see). However, the majority of photos online are still poorly taken, and I frequently see pictures of stones in their box, with incorrect reflections on facets, blurry, or, even worse, with massive fingerprints and no prior cleaning.