Parameterize image max dimension and blob size

Replace the hardcoded POST_IMG_MAX limits baked into the resize helpers
with explicit per-caller maxDimension/maxBytes parameters. Pasted image
URLs now pre-shrink at the high-res 4000px/2MB post limits instead of
2000px/1MB, removing a quality bottleneck before compressImage runs.
Avatar/banner/onboarding and link thumbnails keep their 2000px/1MB
limits.

Also bring web doResize to parity with native by clamping dimensions via
a shared getResizedDimensions (hoisted into media/util.ts), and shadow
the mutated maxDimension param in compressImage as a local.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

__tests__/lib/images.test.ts

@@ -4,8 +4,8 @@ import {manipulateAsync, SaveFormat} from 'expo-image-manipulator'
 import {
   downloadAndResize,
   type DownloadAndResizeOpts,
-  getResizedDimensions,
 } from '../../src/lib/media/manip'
+import {getResizedDimensions} from '../../src/lib/media/util'
 
 const mockResizedImage = {
   path: 'file://resized-image.jpg',
@@ -41,10 +41,8 @@ describe('downloadAndResize', () => {
 
     const opts: DownloadAndResizeOpts = {
       uri: 'https://example.com/image.jpg',
-      width: 100,
-      height: 100,
+      maxDimension: 2000,
       maxSize: 500000,
-      mode: 'cover',
       timeout: 10000,
     }
 
@@ -60,9 +58,11 @@ describe('downloadAndResize', () => {
 
     // First time it gets called is to get dimensions
     expect(manipulateAsync).toHaveBeenCalledWith(expect.any(String), [], {})
+    // The mocked source image is 100x100, below maxDimension, so it is not
+    // downsized.
     expect(manipulateAsync).toHaveBeenCalledWith(
       expect.any(String),
-      [{resize: {height: opts.height, width: opts.width}}],
+      [{resize: {height: 100, width: 100}}],
       {format: SaveFormat.JPEG, compress: 1.0},
     )
     expect(deleteAsync).toHaveBeenCalledWith(expect.any(String), {
@@ -73,10 +73,8 @@ describe('downloadAndResize', () => {
   it('should return undefined for invalid URI', async () => {
     const opts: DownloadAndResizeOpts = {
       uri: 'invalid-uri',
-      width: 100,
-      height: 100,
+      maxDimension: 2000,
       maxSize: 500000,
-      mode: 'cover',
       timeout: 10000,
     }
 

src/lib/api/resolve.ts

@@ -257,9 +257,7 @@ export async function imageToThumb(
   try {
     const img = await downloadAndResize({
       uri: imageUri,
-      width: POST_IMG_MAX.width,
-      height: POST_IMG_MAX.height,
-      mode: 'contain',
+      maxDimension: POST_IMG_MAX.width,
       maxSize: POST_IMG_MAX.size,
       timeout: 15e3,
     })

src/lib/constants.ts

@@ -102,6 +102,12 @@ export const POST_IMG_MAX = {
   size: 1000000,
 }
 
+export const POST_IMG_MAX_HIGH_RES = {
+  width: 4000,
+  height: 4000,
+  size: 2000000,
+}
+
 export const STAGING_LINK_META_PROXY =
   'https://cardyb.staging.bsky.dev/v1/extract?url='
 

src/lib/media/manip.ts

@@ -21,7 +21,7 @@ import {logger} from '#/logger'
 import {IS_ANDROID, IS_IOS} from '#/env'
 import {type PickerImage} from './picker.shared'
 import {type Dimensions} from './types'
-import {convertCdnPreset} from './util'
+import {convertCdnPreset, getResizedDimensions} from './util'
 
 export async function compressIfNeeded(
   img: PickerImage,
@@ -31,9 +31,7 @@ export async function compressIfNeeded(
     return img
   }
   const resizedImage = await doResize(normalizePath(img.path), {
-    width: img.width,
-    height: img.height,
-    mode: 'stretch',
+    maxDimension: POST_IMG_MAX.width,
     maxSize,
   })
   const finalImageMovedPath = await moveToPermanentPath(
@@ -49,9 +47,7 @@ export async function compressIfNeeded(
 
 export interface DownloadAndResizeOpts {
   uri: string
-  width: number
-  height: number
-  mode: 'contain' | 'cover' | 'stretch'
+  maxDimension: number
   maxSize: number
   timeout: number
 }
@@ -67,7 +63,10 @@ export async function downloadAndResize(opts: DownloadAndResizeOpts) {
   const path = await downloadImage(opts.uri, String(uuid.v4()), opts.timeout)
 
   try {
-    return await doResize(path, opts)
+    return await doResize(path, {
+      maxDimension: opts.maxDimension,
+      maxSize: opts.maxSize,
+    })
   } finally {
     void safeDeleteAsync(path)
   }
@@ -188,9 +187,7 @@ export function getImageDim(path: string): Promise<Dimensions> {
 // =
 
 interface DoResizeOpts {
-  width: number
-  height: number
-  mode: 'contain' | 'cover' | 'stretch'
+  maxDimension: number
   maxSize: number
 }
 
@@ -204,10 +201,13 @@ async function doResize(
   // Performing an "empty" manipulation lets us get the dimensions of the original image. React Native's Image.getSize()
   // does not work for local files...
   const imageRes = await manipulateAsync(localUri, [], {})
-  const newDimensions = getResizedDimensions({
-    width: imageRes.width,
-    height: imageRes.height,
-  })
+  const newDimensions = getResizedDimensions(
+    {
+      width: imageRes.width,
+      height: imageRes.height,
+    },
+    {width: opts.maxDimension, height: opts.maxDimension},
+  )
 
   let minQualityPercentage = 0
   let maxQualityPercentage = 101 // exclusive
@@ -388,28 +388,6 @@ async function withTempFile<T>(
   }
 }
 
-export function getResizedDimensions(originalDims: {
-  width: number
-  height: number
-}) {
-  if (
-    originalDims.width <= POST_IMG_MAX.width &&
-    originalDims.height <= POST_IMG_MAX.height
-  ) {
-    return originalDims
-  }
-
-  const ratio = Math.min(
-    POST_IMG_MAX.width / originalDims.width,
-    POST_IMG_MAX.height / originalDims.height,
-  )
-
-  return {
-    width: Math.round(originalDims.width * ratio),
-    height: Math.round(originalDims.height * ratio),
-  }
-}
-
 async function downloadImage(uri: string, destName: string, timeout: number) {
   // Download to a temp path first, then rename with the correct extension
   // based on the response's mimeType.

src/lib/media/manip.web.ts

@@ -1,6 +1,12 @@
+import {POST_IMG_MAX} from '#/lib/constants'
 import {type PickerImage} from './picker.shared'
 import {type Dimensions} from './types'
-import {blobToDataUri, convertCdnPreset, getDataUriSize} from './util'
+import {
+  blobToDataUri,
+  convertCdnPreset,
+  getDataUriSize,
+  getResizedDimensions,
+} from './util'
 
 export async function compressIfNeeded(
   img: PickerImage,
@@ -10,18 +16,14 @@ export async function compressIfNeeded(
     return img
   }
   return await doResize(img.path, {
-    width: img.width,
-    height: img.height,
-    mode: 'stretch',
+    maxDimension: POST_IMG_MAX.width,
     maxSize,
   })
 }
 
 export interface DownloadAndResizeOpts {
   uri: string
-  width: number
-  height: number
-  mode: 'contain' | 'cover' | 'stretch'
+  maxDimension: number
   maxSize: number
   timeout: number
 }
@@ -34,7 +36,10 @@ export async function downloadAndResize(opts: DownloadAndResizeOpts) {
   clearTimeout(to)
 
   const dataUri = await blobToDataUri(resBody)
-  return await doResize(dataUri, opts)
+  return await doResize(dataUri, {
+    maxDimension: opts.maxDimension,
+    maxSize: opts.maxSize,
+  })
 }
 
 export async function shareImageModal(_opts: {uri: string}) {
@@ -70,9 +75,7 @@ export async function getImageDim(path: string): Promise<Dimensions> {
 // =
 
 interface DoResizeOpts {
-  width: number
-  height: number
-  mode: 'contain' | 'cover' | 'stretch'
+  maxDimension: number
   maxSize: number
 }
 
@@ -80,6 +83,12 @@ async function doResize(
   dataUri: string,
   opts: DoResizeOpts,
 ): Promise<PickerImage> {
+  const sourceDims = await getImageDim(dataUri)
+  const newDimensions = getResizedDimensions(sourceDims, {
+    width: opts.maxDimension,
+    height: opts.maxDimension,
+  })
+
   let newDataUri
 
   let minQualityPercentage = 0
@@ -90,10 +99,10 @@ async function doResize(
       (maxQualityPercentage + minQualityPercentage) / 2,
     )
     const tempDataUri = await createResizedImage(dataUri, {
-      width: opts.width,
-      height: opts.height,
+      width: newDimensions.width,
+      height: newDimensions.height,
       quality: qualityPercentage / 100,
-      mode: opts.mode,
+      mode: 'contain',
     })
 
     if (getDataUriSize(tempDataUri) < opts.maxSize) {
@@ -111,8 +120,8 @@ async function doResize(
     path: newDataUri,
     mime: 'image/jpeg',
     size: getDataUriSize(newDataUri),
-    width: opts.width,
-    height: opts.height,
+    width: newDimensions.width,
+    height: newDimensions.height,
   }
 }
 

src/lib/media/util.ts

@@ -1,7 +1,31 @@
+import {POST_IMG_MAX} from '#/lib/constants'
+
 export function extractDataUriMime(uri: string): string {
   return uri.substring(uri.indexOf(':') + 1, uri.indexOf(';'))
 }
 
+export function getResizedDimensions(
+  originalDims: {
+    width: number
+    height: number
+  },
+  max: {width: number; height: number} = POST_IMG_MAX,
+) {
+  if (originalDims.width <= max.width && originalDims.height <= max.height) {
+    return originalDims
+  }
+
+  const ratio = Math.min(
+    max.width / originalDims.width,
+    max.height / originalDims.height,
+  )
+
+  return {
+    width: Math.round(originalDims.width * ratio),
+    height: Math.round(originalDims.height * ratio),
+  }
+}
+
 // Fairly accurate estimate that is more performant
 // than decoding and checking length of URI
 export function getDataUriSize(uri: string): number {

src/state/gallery.ts

@@ -13,6 +13,7 @@ import {
 } from 'expo-image-manipulator'
 import {nanoid} from 'nanoid/non-secure'
 
+import {POST_IMG_MAX_HIGH_RES} from '#/lib/constants'
 import {getImageDim} from '#/lib/media/manip'
 import {openCropper} from '#/lib/media/picker'
 import {type PickerImage} from '#/lib/media/picker.shared'
@@ -201,12 +202,19 @@ export function resetImageManipulation(
   return img
 }
 
-export async function compressImage(img: ComposerImage): Promise<PickerImage> {
+export async function compressImage(
+  img: ComposerImage,
+  {
+    maxDimension = POST_IMG_MAX_HIGH_RES.width,
+    maxBytes = POST_IMG_MAX_HIGH_RES.size,
+  }: {maxDimension?: number; maxBytes?: number} = {},
+): Promise<PickerImage> {
   const source = img.transformed || img.source
 
   let attempts = 0
-  let maxDimension = 4000
-  let maxBytes = 2000000
+  // Seeded from `maxDimension` but shrunk per attempt below, so keep the param
+  // itself pristine.
+  let currentDimension = maxDimension
 
   let minQualityPercentage = 0
   let maxQualityPercentage = 101 // exclusive
@@ -215,7 +223,11 @@ export async function compressImage(img: ComposerImage): Promise<PickerImage> {
   while (maxQualityPercentage - minQualityPercentage > 1) {
     if (attempts >= 4) break
 
-    const [w, h] = containImageRes(source.width, source.height, maxDimension)
+    const [w, h] = containImageRes(
+      source.width,
+      source.height,
+      currentDimension,
+    )
     const qualityPercentage = Math.round(
       (maxQualityPercentage + minQualityPercentage) / 2,
     )
@@ -231,7 +243,7 @@ export async function compressImage(img: ComposerImage): Promise<PickerImage> {
       maxQualityPercentage = 101
       attempts++
       // 4000px → 3200px → 2560px → 2048px → ~1638px
-      maxDimension = Math.floor(maxDimension * 0.8)
+      currentDimension = Math.floor(currentDimension * 0.8)
       continue
     }
 

src/view/com/composer/text-input/TextInput.tsx

@@ -16,7 +16,7 @@ import {type PasteEventPayload, TextInputWrapper} from 'expo-paste-input'
 import {AppBskyRichtextFacet, RichText} from '@atproto/api'
 import {useLingui} from '@lingui/react/macro'
 
-import {POST_IMG_MAX} from '#/lib/constants'
+import {POST_IMG_MAX_HIGH_RES} from '#/lib/constants'
 import {downloadAndResize} from '#/lib/media/manip'
 import {isUriImage} from '#/lib/media/util'
 import {getMentionAt, insertMentionAt} from '#/lib/strings/mention-manip'
@@ -93,10 +93,8 @@ export function TextInput({
               if (isUriImage(feature.uri)) {
                 const res = await downloadAndResize({
                   uri: feature.uri,
-                  width: POST_IMG_MAX.width,
-                  height: POST_IMG_MAX.height,
-                  mode: 'contain',
-                  maxSize: POST_IMG_MAX.size,
+                  maxDimension: POST_IMG_MAX_HIGH_RES.width,
+                  maxSize: POST_IMG_MAX_HIGH_RES.size,
                   timeout: 15e3,
                 })