type ImageField = {
  label: string
  name: string
  type: 'image'
  list?: boolean
  // See https://tina.io/docs/extending-tina/overview/ for customizing the UI
  ui?: {
    label?: string
    description?: string
    component?: FC<any> | string | null
    parse?: (value: string, name: string, field: F) => any
    format?: (value: string, name: string, field: F) => any
    validate?(
      value: string,
      allValues: any,
      meta: any,
      field: UIField<F, Shape>
    ): string | undefined | void
  }
}

export default defineConfig({
  //...
  schema: {
    collections: [
      {
        name: 'posts',
        label: 'Blog Posts',
        path: 'content/posts',
        format: 'mdx',
        fields: [
          {
            type: 'image',
            label: 'Hero image',
            name: 'imgSrc',
          },
          // ... other fields
        ],
      },
    ],
  },
})
// ...

//tina/config.ts

// fields
// ...
{
  type: "image",
  name: "heroImg",
  label: "Hero Image",
  ui: {
    format(value) {
      //add leading slash to value if it doesnt exist
      return value.startsWith("/") ? value : `/${value}`;
    },
    parse(value) {
      //remove leading slash if it exists
      return value.startsWith("/") ? value.slice(1) : value;
    },
  }
}