An image can need more than one kind of description. A placement instruction tells the builder how to use it. A visible caption explains context to readers. Alternative text communicates important visual meaning to people who cannot see the image. These roles can overlap, but they are not interchangeable.
Tell the builder what you intend
Describe what the image shows and why you are adding it. For example: “This is the chair I restored. Put it beside the restoration project, after the before image.” Include any cropping preference that matters. Do not ask the builder to infer a customer endorsement, a location or a product specification that is not established by your facts.
Use captions for context
A caption can name a project, give a date or explain which stage is shown. It should add useful information rather than repeat the heading. If the image is a fictional concept or a practice project, label that context clearly. Check names and dates before publishing.
Describe meaning rather than every pixel
Alternative text should convey what the image contributes in its context. A project photograph might need a short description of the completed piece. A decorative flourish may need an empty alternative so it is skipped. If an image contains important instructions or prices, provide that information as actual page text as well.
Review with the surrounding section
Read the heading, paragraph, caption and image description together. Remove repeated wording that makes the page tiring to navigate. Check whether a visitor can understand the key message when the image fails to load. Text should not claim an image proves something that it does not show.
When adding images in VollSite, provide a description of their role and inspect the generated placement after the requested change completes. Keep your original files separately and use only material you can publish. For foundational accessibility guidance, see https://web.dev/learn/design/accessibility. Automated checks can find some missing descriptions, but a person still needs to judge whether the wording communicates the right meaning.