@ridiculusmus I could look something up on that regard, but maybe @feditips can also help. you could also try to get feedback from blind & low-vision fedizens as well when you post your captioned images.

in general, I myself try to be progressive when describing photographic images, moving from first field to second to background, trying to find a balance between objective description and vivid focus on the subject matter. when they are screen captures, I try to remain informational, focusing on any text that might be present and context. when it comes to visual art I try to imprint some poetry without imposing my subjective vision of the piece, so it can come across as something not only to be described but also felt. otherwise, I try to best serve image, context and function.