I sell plants on trademe and try to give people a fair go. You may be defeating the purpose to ask for a picture of the actual plant as it means that stem plants need to be picked and photographed then on trade me , then wait for payment to clear and to beginning of week to send. The plants could be in unfavourable conditions for 2 weeks. I post representative pictures of the actual plant for sale rather than pinching pictures off the internet, but I prefer not to disturb the plants until just before puting in the post.
(apart from the one in the pic). If people are not happy with what they receive I would hope they would Email me and give me the chance to remedy the situation rather than posting bad comments straight off. It is not always easy: If they go missing in the post it is not my fault but if I say I will replace them them then I will have lots of people claiming they went missing. We do our best and hopefully most people are happy and at least get plants that have a better chance of surviving than many from the pet shop. And hopefully some that are not generally available.