Apply Sanity crop and hotspot to images

Fetch the full image objects instead of only the asset URL so the URL
builder can apply the crop and hotspot set in the Studio, crop the Open
Graph image around the hotspot, and add sizes to full-width blog images.

Closes #27

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/app/[locale]/blog/[slug]/page.tsx

@@ -2,7 +2,7 @@ import Footer from "@/components/page-sections/footer"
 import { generateSeoMetadata } from "@/components/seo"
 import Back from "@/components/ui/back"
 
-import { urlFor } from "@/lib/imageUrlBuilder"
+import { type SanityImage, urlFor } from "@/lib/imageUrlBuilder"
 import { getBlogPost } from "@/lib/sanity"
 
 import { PortableText, PortableTextComponents } from "@portabletext/react"
@@ -20,11 +20,7 @@ interface BlogPageParams {
   }>
 }
 
-interface ImageValue {
-  asset?: {
-    _id: string
-    url: string
-  }
+type ImageValue = Partial<SanityImage> & {
   alt?: string
   caption?: string
 }
@@ -67,7 +63,10 @@ export async function generateMetadata({
     path: `/blog/${slug}`,
     title: data.title,
     description: data.excerpt,
-    imageURL: data.mainImage?.asset?.url,
+    // Cropped around the hotspot to the size link previews expect
+    imageURL: data.mainImage?.asset
+      ? urlFor(data.mainImage).width(1200).height(630).url()
+      : undefined,
     author: data.author?.name,
     publishedTime: data._createdAt,
   })
@@ -80,10 +79,13 @@ const components: PortableTextComponents = {
       return (
         <div className={styles.imageContainer}>
           <Image
-            src={urlFor(value).url()}
+            // Only a width, so the image keeps its shape and just the crop
+            // applies. fit("max") avoids upscaling small images
+            src={urlFor(value).width(1200).fit("max").url()}
             alt={value.alt || "Blog image"}
             width={800}
             height={400}
+            sizes="(max-width: 640px) 100vw, 640px"
             style={{ width: "100%", height: "auto" }}
           />
           {value.caption && (
@@ -144,10 +146,11 @@ const BlogPost = async ({ params }: BlogPageParams) => {
           <header className={styles.header}>
             {data.mainImage && (
               <Image
-                src={urlFor(data.mainImage).url()}
+                src={urlFor(data.mainImage).width(1600).fit("max").url()}
                 alt={data.title}
                 width={800}
                 height={400}
+                sizes="(max-width: 850px) 100vw, 850px"
                 className={styles.headerImage}
               />
             )}
@@ -158,7 +161,7 @@ const BlogPost = async ({ params }: BlogPageParams) => {
                 <Image
                   className="circular"
                   alt={data.author.name}
-                  src={urlFor(data.author.image).width(50).height(50).url()}
+                  src={urlFor(data.author.image).width(100).height(100).url()}
                   width={50}
                   height={50}
                 />

src/components/page-sections/boardMembers.tsx

@@ -1,4 +1,4 @@
-import { urlFor } from "@/lib/imageUrlBuilder"
+import { type SanityImage, urlFor } from "@/lib/imageUrlBuilder"
 import { getBoardMembers } from "@/lib/sanity"
 
 import { getLocale, getTranslations } from "next-intl/server"
@@ -14,12 +14,7 @@ interface BoardMember {
     no: string
     en: string
   }
-  image?: {
-    asset?: {
-      _id: string
-      url: string
-    }
-  }
+  image: SanityImage | null
   bio?: {
     no: string
     en: string
@@ -44,11 +39,9 @@ const BoardMembers = async () => {
               >
                 <Image
                   src={
-                    member.image?.asset?.url
-                      ? urlFor(member.image.asset.url)
-                          .width(512)
-                          .height(512)
-                          .url()
+                    member.image?.asset
+                      ? // Cropped to a square around the hotspot
+                        urlFor(member.image).width(512).height(512).url()
                       : "/person.png"
                   }
                   width={256}

src/lib/imageUrlBuilder.ts

@@ -1,5 +1,6 @@
 import {
   createImageUrlBuilder,
+  type SanityImageObject,
   type SanityImageSource,
 } from "@sanity/image-url"
 
@@ -7,6 +8,11 @@ import { sanityClient } from "./sanity"
 
 const builder = createImageUrlBuilder(sanityClient)
 
+// An image field as stored in Sanity: an asset reference plus the crop and
+// hotspot chosen in the Studio. Pass the whole object to urlFor, not the
+// asset URL, or the crop and hotspot are ignored
+export type SanityImage = SanityImageObject
+
 export function urlFor(source: SanityImageSource) {
   return builder.image(source)
 }

src/lib/sanity.ts

@@ -17,19 +17,9 @@ export async function getBlogPost(slug: string) {
       title,
       author-> {
         name,
-        image {
-          asset-> {
-            _id,
-            url
-          }
-        }
-      },
-      mainImage {
-        asset-> {
-          _id,
-          url
-        }
+        image
       },
+      mainImage,
       excerpt,
       body
     }
@@ -119,12 +109,7 @@ export async function getBoardMembers() {
         no,
         en
       },
-      image {
-        asset->{
-          _id,
-          url
-        }
-      },
+      image,
       bio {
         no,
         en